From e0c771b8b976cee6303a38a4c85eba702dcab460 Mon Sep 17 00:00:00 2001
From: Bayram Tagiev <bayram.tagiev.a@gmail.com>
Date: Thu, 8 Jun 2023 11:51:31 +0300
Subject: [PATCH 1/2] tests: updated outdated data

Results: TESTS/OK/FAILED 24/24/0
---
 tests/results/10 |   33 +-
 tests/results/11 |    2 -
 tests/results/12 |    2 -
 tests/results/15 | 1460 +++++++++++++++++++++++-----------------------
 tests/results/16 |    6 +-
 tests/results/17 |  172 +++---
 tests/results/18 |   18 +-
 tests/results/2  |   78 ++-
 tests/results/21 |  932 ++++++++++++++---------------
 tests/results/22 |  932 ++++++++++++++---------------
 tests/results/23 |    1 +
 tests/results/25 |   35 --
 tests/results/3  |   18 +-
 tests/results/4  |  102 ++--
 tests/results/5  |   75 +--
 tests/results/9  |   33 +-
 16 files changed, 1964 insertions(+), 1935 deletions(-)

diff --git a/tests/results/10 b/tests/results/10
index a8eca4f0..54d42a50 100644
--- a/tests/results/10
+++ b/tests/results/10
@@ -1,16 +1,23 @@
-#  How do I copy a file in Python?
+#  [`shutil`][1] has many methods you can use. One of which is:
 #  
-#  shutil (http://docs.python.org/3/library/shutil.html) has many methods
-#  you can use. One of which is:
-
-from shutil import copyfile
-
-copyfile(src, dst)
-
-#  Copy the contents of the file named src to a file named dst. The
-#  destination location must be writable; otherwise, an IOError exception
-#  will be raised. If dst already exists, it will be replaced. Special
-#  files such as character or block devices and pipes cannot be copied
-#  with this function. src and dst are path names given as strings.
+#  ```
+#  from shutil import copyfile
+#  copyfile(src, dst)
+#  ```
+#  
+ #  - Copy the contents of the file named **src** to a file named
+#  **dst**.
+ #  - The destination location must be writable; otherwise, an
+#  **IOError** exception will be raised.
+ #  - If **dst** already exists, it will be replaced.
+ #  - Special files such as character or block devices and pipes cannot
+#  be copied with this function.
+ #  - With **copy**, **src** and **dst** are path names given as
+#  __strings__.
+#  
+#  If you use `os.path` operations, use `copy` rather than `copyfile`.
+#  `copyfile` will only accept strings.
+#  
+  #  [1]: http://docs.python.org/3/library/shutil.html
 #  
 #  [Swati] [so/q/123198] [cc by-sa 3.0]
diff --git a/tests/results/11 b/tests/results/11
index d0db3d4e..8b137891 100644
--- a/tests/results/11
+++ b/tests/results/11
@@ -1,3 +1 @@
-from shutil import copyfile
 
-copyfile(src, dst)
diff --git a/tests/results/12 b/tests/results/12
index 7c532658..8b137891 100644
--- a/tests/results/12
+++ b/tests/results/12
@@ -1,3 +1 @@
-from shutil import copyfile
 
-copyfile(src, dst)
diff --git a/tests/results/15 b/tests/results/15
index ad1f1a9e..c6335a4d 100644
--- a/tests/results/15
+++ b/tests/results/15
@@ -1,383 +1,388 @@
-# Single line comments start with a number symbol.
+# Single line comments start with a number symbol.
 
 """ Multiline strings can be written
     using three "s, and are often used
     as documentation.
 """
 
-####################################################
-## 1. Primitive Datatypes and Operators
-####################################################
-
-# You have numbers
-3  # => 3
-
-# Math is what you would expect
-1 + 1   # => 2
-8 - 1   # => 7
-10 * 2  # => 20
-35 / 5  # => 7.0
-
-# Integer division rounds down for both positive and negative numbers.
-5 // 3       # => 1
--5 // 3      # => -2
-5.0 // 3.0   # => 1.0 # works on floats too
--5.0 // 3.0  # => -2.0
-
-# The result of division is always a float
-10.0 / 3  # => 3.3333333333333335
-
-# Modulo operation
-7 % 3   # => 1
-# i % j have the same sign as j, unlike C
--7 % 3  # => 2
-
-# Exponentiation (x**y, x to the yth power)
-2**3  # => 8
-
-# Enforce precedence with parentheses
-1 + 3 * 2    # => 7
-(1 + 3) * 2  # => 8
-
-# Boolean values are primitives (Note: the capitalization)
-True   # => True
-False  # => False
-
-# negate with not
-not True   # => False
-not False  # => True
-
-# Boolean Operators
-# Note "and" and "or" are case-sensitive
-True and False  # => False
-False or True   # => True
-
-# True and False are actually 1 and 0 but with different keywords
-True + True # => 2
-True * 8    # => 8
-False - 5   # => -5
-
-# Comparison operators look at the numerical value of True and False
-0 == False  # => True
-1 == True   # => True
-2 == True   # => False
--5 != False # => True
-
-# Using boolean logical operators on ints casts them to booleans for evaluation, but their non-cast value is returned
-# Don't mix up with bool(ints) and bitwise and/or (&,|)
-bool(0)     # => False
-bool(4)     # => True
-bool(-6)    # => True
-0 and 2     # => 0
--5 or 0     # => -5
-
-# Equality is ==
-1 == 1  # => True
-2 == 1  # => False
-
-# Inequality is !=
-1 != 1  # => False
-2 != 1  # => True
-
-# More comparisons
-1 < 10  # => True
-1 > 10  # => False
-2 <= 2  # => True
-2 >= 2  # => True
-
-# Seeing whether a value is in a range
-1 < 2 and 2 < 3  # => True
-2 < 3 and 3 < 2  # => False
-# Chaining makes this look nicer
-1 < 2 < 3  # => True
-2 < 3 < 2  # => False
-
-# (is vs. ==) is checks if two variables refer to the same object, but == checks
-# if the objects pointed to have the same values.
-a = [1, 2, 3, 4]  # Point a at a new list, [1, 2, 3, 4]
-b = a             # Point b at what a is pointing to
-b is a            # => True, a and b refer to the same object
-b == a            # => True, a's and b's objects are equal
-b = [1, 2, 3, 4]  # Point b at a new list, [1, 2, 3, 4]
-b is a            # => False, a and b do not refer to the same object
-b == a            # => True, a's and b's objects are equal
-
-# Strings are created with " or '
+####################################################
+## 1. Primitive Datatypes and Operators
+####################################################
+
+# You have numbers
+3  # => 3
+
+# Math is what you would expect
+1 + 1   # => 2
+8 - 1   # => 7
+10 * 2  # => 20
+35 / 5  # => 7.0
+
+# Integer division rounds down for both positive and negative numbers.
+5 // 3       # => 1
+-5 // 3      # => -2
+5.0 // 3.0   # => 1.0 # works on floats too
+-5.0 // 3.0  # => -2.0
+
+# The result of division is always a float
+10.0 / 3  # => 3.3333333333333335
+
+# Modulo operation
+7 % 3   # => 1
+# i % j have the same sign as j, unlike C
+-7 % 3  # => 2
+
+# Exponentiation (x**y, x to the yth power)
+2**3  # => 8
+
+# Enforce precedence with parentheses
+1 + 3 * 2    # => 7
+(1 + 3) * 2  # => 8
+
+# Boolean values are primitives (Note: the capitalization)
+True   # => True
+False  # => False
+
+# negate with not
+not True   # => False
+not False  # => True
+
+# Boolean Operators
+# Note "and" and "or" are case-sensitive
+True and False  # => False
+False or True   # => True
+
+# True and False are actually 1 and 0 but with different keywords
+True + True # => 2
+True * 8    # => 8
+False - 5   # => -5
+
+# Comparison operators look at the numerical value of True and False
+0 == False  # => True
+2 > True    # => True
+2 == True   # => False
+-5 != False # => True
+
+# None, 0, and empty strings/lists/dicts/tuples/sets all evaluate to False.
+# All other values are True
+bool(0)     # => False
+bool("")    # => False
+bool([])    # => False
+bool({})    # => False
+bool(())    # => False
+bool(set()) # => False
+bool(4)     # => True
+bool(-6)    # => True
+
+# Using boolean logical operators on ints casts them to booleans for evaluation,
+# but their non-cast value is returned. Don't mix up with bool(ints) and bitwise
+# and/or (&,|)
+bool(0)     # => False
+bool(2)     # => True
+0 and 2     # => 0
+bool(-5)    # => True
+bool(2)     # => True
+-5 or 0     # => -5
+
+# Equality is ==
+1 == 1  # => True
+2 == 1  # => False
+
+# Inequality is !=
+1 != 1  # => False
+2 != 1  # => True
+
+# More comparisons
+1 < 10  # => True
+1 > 10  # => False
+2 <= 2  # => True
+2 >= 2  # => True
+
+# Seeing whether a value is in a range
+1 < 2 and 2 < 3  # => True
+2 < 3 and 3 < 2  # => False
+# Chaining makes this look nicer
+1 < 2 < 3  # => True
+2 < 3 < 2  # => False
+
+# (is vs. ==) is checks if two variables refer to the same object, but == checks
+# if the objects pointed to have the same values.
+a = [1, 2, 3, 4]  # Point a at a new list, [1, 2, 3, 4]
+b = a             # Point b at what a is pointing to
+b is a            # => True, a and b refer to the same object
+b == a            # => True, a's and b's objects are equal
+b = [1, 2, 3, 4]  # Point b at a new list, [1, 2, 3, 4]
+b is a            # => False, a and b do not refer to the same object
+b == a            # => True, a's and b's objects are equal
+
+# Strings are created with " or '
 "This is a string."
 'This is also a string.'
 
-# Strings can be added too
-"Hello " + "world!"  # => "Hello world!"
-# String literals (but not variables) can be concatenated without using '+'
-"Hello " "world!"    # => "Hello world!"
+# Strings can be added too
+"Hello " + "world!"  # => "Hello world!"
+# String literals (but not variables) can be concatenated without using '+'
+"Hello " "world!"    # => "Hello world!"
 
-# A string can be treated like a list of characters
-"Hello world!"[0]  # => 'H'
+# A string can be treated like a list of characters
+"Hello world!"[0]  # => 'H'
 
-# You can find the length of a string
-len("This is a string")  # => 16
+# You can find the length of a string
+len("This is a string")  # => 16
 
-# You can also format using f-strings or formatted string literals (in Python 3.6+)
+# Since Python 3.6, you can use f-strings or formatted string literals.
 name = "Reiko"
-f"She said her name is {name}." # => "She said her name is Reiko"
-# You can basically put any Python expression inside the braces and it will be output in the string.
-f"{name} is {len(name)} characters long." # => "Reiko is 5 characters long."
-
-# None is an object
-None  # => None
-
-# Don't use the equality "==" symbol to compare objects to None
-# Use "is" instead. This checks for equality of object identity.
-"etc" is None  # => False
-None is None   # => True
-
-# None, 0, and empty strings/lists/dicts/tuples all evaluate to False.
-# All other values are True
-bool(0)   # => False
-bool("")  # => False
-bool([])  # => False
-bool({})  # => False
-bool(())  # => False
-
-####################################################
-## 2. Variables and Collections
-####################################################
-
-# Python has a print function
-print("I'm Python. Nice to meet you!")  # => I'm Python. Nice to meet you!
-
-# By default the print function also prints out a newline at the end.
-# Use the optional argument end to change the end string.
-print("Hello, World", end="!")  # => Hello, World!
-
-# Simple way to get input data from console
-input_string_var = input("Enter some data: ") # Returns the data as a string
-
-# There are no declarations, only assignments.
-# Convention is to use lower_case_with_underscores
-some_var = 5
-some_var  # => 5
-
-# Accessing a previously unassigned variable is an exception.
-# See Control Flow to learn more about exception handling.
-some_unknown_var  # Raises a NameError
-
-# if can be used as an expression
-# Equivalent of C's '?:' ternary operator
-"yay!" if 0 > 1 else "nay!"  # => "nay!"
-
-# Lists store sequences
+f"She said her name is {name}." # => "She said her name is Reiko"
+# Any valid Python expression inside these braces is returned to the string.
+f"{name} is {len(name)} characters long." # => "Reiko is 5 characters long."
+
+# None is an object
+None  # => None
+
+# Don't use the equality "==" symbol to compare objects to None
+# Use "is" instead. This checks for equality of object identity.
+"etc" is None  # => False
+None is None   # => True
+
+####################################################
+## 2. Variables and Collections
+####################################################
+
+# Python has a print function
+print("I'm Python. Nice to meet you!")  # => I'm Python. Nice to meet you!
+
+# By default the print function also prints out a newline at the end.
+# Use the optional argument end to change the end string.
+print("Hello, World", end="!")  # => Hello, World!
+
+# Simple way to get input data from console
+input_string_var = input("Enter some data: ") # Returns the data as a string
+
+# There are no declarations, only assignments.
+# Convention is to use lower_case_with_underscores
+some_var = 5
+some_var  # => 5
+
+# Accessing a previously unassigned variable is an exception.
+# See Control Flow to learn more about exception handling.
+some_unknown_var  # Raises a NameError
+
+# if can be used as an expression
+# Equivalent of C's '?:' ternary operator
+"yay!" if 0 > 1 else "nay!"  # => "nay!"
+
+# Lists store sequences
 li = []
-# You can start with a prefilled list
-other_li = [4, 5, 6]
-
-# Add stuff to the end of a list with append
-li.append(1)    # li is now [1]
-li.append(2)    # li is now [1, 2]
-li.append(4)    # li is now [1, 2, 4]
-li.append(3)    # li is now [1, 2, 4, 3]
-# Remove from the end with pop
-li.pop()        # => 3 and li is now [1, 2, 4]
-# Let's put it back
-li.append(3)    # li is now [1, 2, 4, 3] again.
-
-# Access a list like you would any array
-li[0]   # => 1
-# Look at the last element
-li[-1]  # => 3
-
-# Looking out of bounds is an IndexError
-li[4]  # Raises an IndexError
-
-# You can look at ranges with slice syntax.
-# The start index is included, the end index is not
-# (It's a closed/open range for you mathy types.)
-li[1:3]   # Return list from index 1 to 3 => [2, 4]
-li[2:]    # Return list starting from index 2 => [4, 3]
-li[:3]    # Return list from beginning until index 3  => [1, 2, 4]
-li[::2]   # Return list selecting every second entry => [1, 4]
-li[::-1]  # Return list in reverse order => [3, 4, 2, 1]
-# Use any combination of these to make advanced slices
-# li[start:end:step]
-
-# Make a one layer deep copy using slices
-li2 = li[:]  # => li2 = [1, 2, 4, 3] but (li2 is li) will result in false.
-
-# Remove arbitrary elements from a list with "del"
-del li[2]  # li is now [1, 2, 3]
-
-# Remove first occurrence of a value
-li.remove(2)  # li is now [1, 3]
-li.remove(2)  # Raises a ValueError as 2 is not in the list
-
-# Insert an element at a specific index
-li.insert(1, 2)  # li is now [1, 2, 3] again
-
-# Get the index of the first item found matching the argument
-li.index(2)  # => 1
-li.index(4)  # Raises a ValueError as 4 is not in the list
-
-# You can add lists
-# Note: values for li and for other_li are not modified.
-li + other_li  # => [1, 2, 3, 4, 5, 6]
-
-# Concatenate lists with "extend()"
-li.extend(other_li)  # Now li is [1, 2, 3, 4, 5, 6]
-
-# Check for existence in a list with "in"
-1 in li  # => True
-
-# Examine the length with "len()"
-len(li)  # => 6
-
-
-# Tuples are like lists but are immutable.
-tup = (1, 2, 3)
-tup[0]      # => 1
-tup[0] = 3  # Raises a TypeError
-
-# Note that a tuple of length one has to have a comma after the last element but
-# tuples of other lengths, even zero, do not.
-type((1))   # => <class 'int'>
-type((1,))  # => <class 'tuple'>
-type(())    # => <class 'tuple'>
-
-# You can do most of the list operations on tuples too
-len(tup)         # => 3
-tup + (4, 5, 6)  # => (1, 2, 3, 4, 5, 6)
-tup[:2]          # => (1, 2)
-2 in tup         # => True
-
-# You can unpack tuples (or lists) into variables
-a, b, c = (1, 2, 3)  # a is now 1, b is now 2 and c is now 3
-# You can also do extended unpacking
-a, *b, c = (1, 2, 3, 4)  # a is now 1, b is now [2, 3] and c is now 4
-# Tuples are created by default if you leave out the parentheses
-d, e, f = 4, 5, 6  # tuple 4, 5, 6 is unpacked into variables d, e and f
-# respectively such that d = 4, e = 5 and f = 6
-# Now look how easy it is to swap two values
-e, d = d, e  # d is now 5 and e is now 4
-
-
-# Dictionaries store mappings from keys to values
+# You can start with a prefilled list
+other_li = [4, 5, 6]
+
+# Add stuff to the end of a list with append
+li.append(1)    # li is now [1]
+li.append(2)    # li is now [1, 2]
+li.append(4)    # li is now [1, 2, 4]
+li.append(3)    # li is now [1, 2, 4, 3]
+# Remove from the end with pop
+li.pop()        # => 3 and li is now [1, 2, 4]
+# Let's put it back
+li.append(3)    # li is now [1, 2, 4, 3] again.
+
+# Access a list like you would any array
+li[0]   # => 1
+# Look at the last element
+li[-1]  # => 3
+
+# Looking out of bounds is an IndexError
+li[4]  # Raises an IndexError
+
+# You can look at ranges with slice syntax.
+# The start index is included, the end index is not
+# (It's a closed/open range for you mathy types.)
+li[1:3]   # Return list from index 1 to 3 => [2, 4]
+li[2:]    # Return list starting from index 2 => [4, 3]
+li[:3]    # Return list from beginning until index 3  => [1, 2, 4]
+li[::2]   # Return list selecting every second entry => [1, 4]
+li[::-1]  # Return list in reverse order => [3, 4, 2, 1]
+# Use any combination of these to make advanced slices
+# li[start:end:step]
+
+# Make a one layer deep copy using slices
+li2 = li[:]  # => li2 = [1, 2, 4, 3] but (li2 is li) will result in false.
+
+# Remove arbitrary elements from a list with "del"
+del li[2]  # li is now [1, 2, 3]
+
+# Remove first occurrence of a value
+li.remove(2)  # li is now [1, 3]
+li.remove(2)  # Raises a ValueError as 2 is not in the list
+
+# Insert an element at a specific index
+li.insert(1, 2)  # li is now [1, 2, 3] again
+
+# Get the index of the first item found matching the argument
+li.index(2)  # => 1
+li.index(4)  # Raises a ValueError as 4 is not in the list
+
+# You can add lists
+# Note: values for li and for other_li are not modified.
+li + other_li  # => [1, 2, 3, 4, 5, 6]
+
+# Concatenate lists with "extend()"
+li.extend(other_li)  # Now li is [1, 2, 3, 4, 5, 6]
+
+# Check for existence in a list with "in"
+1 in li  # => True
+
+# Examine the length with "len()"
+len(li)  # => 6
+
+
+# Tuples are like lists but are immutable.
+tup = (1, 2, 3)
+tup[0]      # => 1
+tup[0] = 3  # Raises a TypeError
+
+# Note that a tuple of length one has to have a comma after the last element but
+# tuples of other lengths, even zero, do not.
+type((1))   # => <class 'int'>
+type((1,))  # => <class 'tuple'>
+type(())    # => <class 'tuple'>
+
+# You can do most of the list operations on tuples too
+len(tup)         # => 3
+tup + (4, 5, 6)  # => (1, 2, 3, 4, 5, 6)
+tup[:2]          # => (1, 2)
+2 in tup         # => True
+
+# You can unpack tuples (or lists) into variables
+a, b, c = (1, 2, 3)  # a is now 1, b is now 2 and c is now 3
+# You can also do extended unpacking
+a, *b, c = (1, 2, 3, 4)  # a is now 1, b is now [2, 3] and c is now 4
+# Tuples are created by default if you leave out the parentheses
+d, e, f = 4, 5, 6  # tuple 4, 5, 6 is unpacked into variables d, e and f
+# respectively such that d = 4, e = 5 and f = 6
+# Now look how easy it is to swap two values
+e, d = d, e  # d is now 5 and e is now 4
+
+
+# Dictionaries store mappings from keys to values
 empty_dict = {}
-# Here is a prefilled dictionary
-filled_dict = {"one": 1, "two": 2, "three": 3}
+# Here is a prefilled dictionary
+filled_dict = {"one": 1, "two": 2, "three": 3}
 
-# Note keys for dictionaries have to be immutable types. This is to ensure that
-# the key can be converted to a constant hash value for quick look-ups.
-# Immutable types include ints, floats, strings, tuples.
-invalid_dict = {[1,2,3]: "123"}  # => Raises a TypeError: unhashable type: 'list'
-valid_dict = {(1,2,3):[1,2,3]}   # Values can be of any type, however.
+# Note keys for dictionaries have to be immutable types. This is to ensure that
+# the key can be converted to a constant hash value for quick look-ups.
+# Immutable types include ints, floats, strings, tuples.
+invalid_dict = {[1,2,3]: "123"}  # => Yield a TypeError: unhashable type: 'list'
+valid_dict = {(1,2,3):[1,2,3]}   # Values can be of any type, however.
 
-# Look up values with []
-filled_dict["one"]  # => 1
+# Look up values with []
+filled_dict["one"]  # => 1
 
-# Get all keys as an iterable with "keys()". We need to wrap the call in list()
-# to turn it into a list. We'll talk about those later.  Note - for Python
-# versions <3.7, dictionary key ordering is not guaranteed. Your results might
-# not match the example below exactly. However, as of Python 3.7, dictionary
-# items maintain the order at which they are inserted into the dictionary.
-list(filled_dict.keys())  # => ["three", "two", "one"] in Python <3.7
-list(filled_dict.keys())  # => ["one", "two", "three"] in Python 3.7+
+# Get all keys as an iterable with "keys()". We need to wrap the call in list()
+# to turn it into a list. We'll talk about those later.  Note - for Python
+# versions <3.7, dictionary key ordering is not guaranteed. Your results might
+# not match the example below exactly. However, as of Python 3.7, dictionary
+# items maintain the order at which they are inserted into the dictionary.
+list(filled_dict.keys())  # => ["three", "two", "one"] in Python <3.7
+list(filled_dict.keys())  # => ["one", "two", "three"] in Python 3.7+
 
 
-# Get all values as an iterable with "values()". Once again we need to wrap it
-# in list() to get it out of the iterable. Note - Same as above regarding key
-# ordering.
-list(filled_dict.values())  # => [3, 2, 1]  in Python <3.7
-list(filled_dict.values())  # => [1, 2, 3] in Python 3.7+
+# Get all values as an iterable with "values()". Once again we need to wrap it
+# in list() to get it out of the iterable. Note - Same as above regarding key
+# ordering.
+list(filled_dict.values())  # => [3, 2, 1]  in Python <3.7
+list(filled_dict.values())  # => [1, 2, 3] in Python 3.7+
 
-# Check for existence of keys in a dictionary with "in"
-"one" in filled_dict  # => True
-1 in filled_dict      # => False
+# Check for existence of keys in a dictionary with "in"
+"one" in filled_dict  # => True
+1 in filled_dict      # => False
 
-# Looking up a non-existing key is a KeyError
-filled_dict["four"]  # KeyError
+# Looking up a non-existing key is a KeyError
+filled_dict["four"]  # KeyError
 
-# Use "get()" method to avoid the KeyError
-filled_dict.get("one")      # => 1
-filled_dict.get("four")     # => None
-# The get method supports a default argument when the value is missing
-filled_dict.get("one", 4)   # => 1
-filled_dict.get("four", 4)  # => 4
+# Use "get()" method to avoid the KeyError
+filled_dict.get("one")      # => 1
+filled_dict.get("four")     # => None
+# The get method supports a default argument when the value is missing
+filled_dict.get("one", 4)   # => 1
+filled_dict.get("four", 4)  # => 4
 
-# "setdefault()" inserts into a dictionary only if the given key isn't present
-filled_dict.setdefault("five", 5)  # filled_dict["five"] is set to 5
-filled_dict.setdefault("five", 6)  # filled_dict["five"] is still 5
+# "setdefault()" inserts into a dictionary only if the given key isn't present
+filled_dict.setdefault("five", 5)  # filled_dict["five"] is set to 5
+filled_dict.setdefault("five", 6)  # filled_dict["five"] is still 5
 
-# Adding to a dictionary
-filled_dict.update({"four":4})  # => {"one": 1, "two": 2, "three": 3, "four": 4}
-filled_dict["four"] = 4         # another way to add to dict
+# Adding to a dictionary
+filled_dict.update({"four":4})  # => {"one": 1, "two": 2, "three": 3, "four": 4}
+filled_dict["four"] = 4         # another way to add to dict
 
-# Remove keys from a dictionary with del
-del filled_dict["one"]  # Removes the key "one" from filled dict
+# Remove keys from a dictionary with del
+del filled_dict["one"]  # Removes the key "one" from filled dict
 
-# From Python 3.5 you can also use the additional unpacking options
-{'a': 1, **{'b': 2}}  # => {'a': 1, 'b': 2}
-{'a': 1, **{'a': 2}}  # => {'a': 2}
+# From Python 3.5 you can also use the additional unpacking options
+{'a': 1, **{'b': 2}}  # => {'a': 1, 'b': 2}
+{'a': 1, **{'a': 2}}  # => {'a': 2}
 
 
 
-# Sets store ... well sets
-empty_set = set()
-# Initialize a set with a bunch of values. Yeah, it looks a bit like a dict. Sorry.
-some_set = {1, 1, 2, 2, 3, 4}  # some_set is now {1, 2, 3, 4}
+# Sets store ... well sets
+empty_set = set()
+# Initialize a set with a bunch of values.
+some_set = {1, 1, 2, 2, 3, 4}  # some_set is now {1, 2, 3, 4}
 
-# Similar to keys of a dictionary, elements of a set have to be immutable.
-invalid_set = {[1], 1}  # => Raises a TypeError: unhashable type: 'list'
-valid_set = {(1,), 1}
+# Similar to keys of a dictionary, elements of a set have to be immutable.
+invalid_set = {[1], 1}  # => Raises a TypeError: unhashable type: 'list'
+valid_set = {(1,), 1}
 
-# Add one more item to the set
+# Add one more item to the set
 filled_set = some_set
-filled_set.add(5)  # filled_set is now {1, 2, 3, 4, 5}
-# Sets do not have duplicate elements
-filled_set.add(5)  # it remains as before {1, 2, 3, 4, 5}
+filled_set.add(5)  # filled_set is now {1, 2, 3, 4, 5}
+# Sets do not have duplicate elements
+filled_set.add(5)  # it remains as before {1, 2, 3, 4, 5}
 
-# Do set intersection with &
-other_set = {3, 4, 5, 6}
-filled_set & other_set  # => {3, 4, 5}
+# Do set intersection with &
+other_set = {3, 4, 5, 6}
+filled_set & other_set  # => {3, 4, 5}
 
-# Do set union with |
-filled_set | other_set  # => {1, 2, 3, 4, 5, 6}
+# Do set union with |
+filled_set | other_set  # => {1, 2, 3, 4, 5, 6}
 
-# Do set difference with -
-{1, 2, 3, 4} - {2, 3, 5}  # => {1, 4}
+# Do set difference with -
+{1, 2, 3, 4} - {2, 3, 5}  # => {1, 4}
 
-# Do set symmetric difference with ^
-{1, 2, 3, 4} ^ {2, 3, 5}  # => {1, 4, 5}
+# Do set symmetric difference with ^
+{1, 2, 3, 4} ^ {2, 3, 5}  # => {1, 4, 5}
 
-# Check if set on the left is a superset of set on the right
-{1, 2} >= {1, 2, 3} # => False
+# Check if set on the left is a superset of set on the right
+{1, 2} >= {1, 2, 3} # => False
 
-# Check if set on the left is a subset of set on the right
-{1, 2} <= {1, 2, 3} # => True
+# Check if set on the left is a subset of set on the right
+{1, 2} <= {1, 2, 3} # => True
 
-# Check for existence in a set with in
-2 in filled_set   # => True
-10 in filled_set  # => False
+# Check for existence in a set with in
+2 in filled_set   # => True
+10 in filled_set  # => False
 
-# Make a one layer deep copy
-filled_set = some_set.copy()  # filled_set is {1, 2, 3, 4, 5}
-filled_set is some_set        # => False
+# Make a one layer deep copy
+filled_set = some_set.copy()  # filled_set is {1, 2, 3, 4, 5}
+filled_set is some_set        # => False
 
 
-####################################################
-## 3. Control Flow and Iterables
-####################################################
+####################################################
+## 3. Control Flow and Iterables
+####################################################
 
-# Let's just make a variable
-some_var = 5
+# Let's just make a variable
+some_var = 5
 
-# Here is an if statement. Indentation is significant in Python!
-# Convention is to use four spaces, not tabs.
-# This prints "some_var is smaller than 10"
-if some_var > 10:
-    print("some_var is totally bigger than 10.")
-elif some_var < 10:    # This elif clause is optional.
-    print("some_var is smaller than 10.")
-else:                  # This is optional too.
-    print("some_var is indeed 10.")
+# Here is an if statement. Indentation is significant in Python!
+# Convention is to use four spaces, not tabs.
+# This prints "some_var is smaller than 10"
+if some_var > 10:
+    print("some_var is totally bigger than 10.")
+elif some_var < 10:    # This elif clause is optional.
+    print("some_var is smaller than 10.")
+else:                  # This is optional too.
+    print("some_var is indeed 10.")
 
 
 """
@@ -388,20 +393,20 @@
     mouse is a mammal
 """
 for animal in ["dog", "cat", "mouse"]:
-    # You can use format() to interpolate formatted strings
-    print("{} is a mammal".format(animal))
+    # You can use format() to interpolate formatted strings
+    print("{} is a mammal".format(animal))
 
 """
 "range(number)" returns an iterable of numbers
-from zero to the given number
+from zero up to (but excluding) the given number
 prints:
     0
     1
     2
     3
 """
-for i in range(4):
-    print(i)
+for i in range(4):
+    print(i)
 
 """
 "range(lower, upper)" returns an iterable of numbers
@@ -412,8 +417,8 @@
     6
     7
 """
-for i in range(4, 8):
-    print(i)
+for i in range(4, 8):
+    print(i)
 
 """
 "range(lower, upper, step)" returns an iterable of numbers
@@ -423,19 +428,18 @@
     4
     6
 """
-for i in range(4, 8, 2):
-    print(i)
+for i in range(4, 8, 2):
+    print(i)
 
 """
-To loop over a list, and retrieve both the index and the value of each item in the list
-prints:
+Loop over a list to retrieve both the index and the value of each list item:
     0 dog
     1 cat
     2 mouse
 """
 animals = ["dog", "cat", "mouse"]
-for i, value in enumerate(animals):
-    print(i, value)
+for i, value in enumerate(animals):
+    print(i, value)
 
 """
 While loops go until a condition is no longer met.
@@ -445,544 +449,556 @@
     2
     3
 """
-x = 0
-while x < 4:
-    print(x)
-    x += 1  # Shorthand for x = x + 1
+x = 0
+while x < 4:
+    print(x)
+    x += 1  # Shorthand for x = x + 1
 
-# Handle exceptions with a try/except block
+# Handle exceptions with a try/except block
 try:
-    # Use "raise" to raise an error
+    # Use "raise" to raise an error
     raise IndexError("This is an index error")
 except IndexError as e:
-    pass                 # Pass is just a no-op. Usually you would do recovery here.
+    pass                 # Refrain from this, provide a recovery (next example).
 except (TypeError, NameError):
-    pass                 # Multiple exceptions can be handled together, if required.
-else:                    # Optional clause to the try/except block. Must follow all except blocks
-    print("All good!")   # Runs only if the code in try raises no exceptions
-finally:                 # Execute under all circumstances
-    print("We can clean up resources here")
-
-# Instead of try/finally to cleanup resources you can use a with statement
-with open("myfile.txt") as f:
+    pass                 # Multiple exceptions can be processed jointly.
+else:                    # Optional clause to the try/except block. Must follow
+                         # all except blocks.
+    print("All good!")   # Runs only if the code in try raises no exceptions
+finally:                 # Execute under all circumstances
+    print("We can clean up resources here")
+
+# Instead of try/finally to cleanup resources you can use a with statement
+with open("myfile.txt") as f:
     for line in f:
-        print(line)
+        print(line)
 
-# Writing to a file
-contents = {"aa": 12, "bb": 21}
-with open("myfile1.txt", "w+") as file:
-    file.write(str(contents))        # writes a string to a file
+# Writing to a file
+contents = {"aa": 12, "bb": 21}
+with open("myfile1.txt", "w+") as file:
+    file.write(str(contents))        # writes a string to a file
 
-with open("myfile2.txt", "w+") as file:
-    file.write(json.dumps(contents)) # writes an object to a file
+import json
+with open("myfile2.txt", "w+") as file:
+    file.write(json.dumps(contents)) # writes an object to a file
 
-# Reading from a file
-with open('myfile1.txt', "r+") as file:
-    contents = file.read()           # reads a string from a file
-print(contents)
-# print: {"aa": 12, "bb": 21}
+# Reading from a file
+with open('myfile1.txt', "r+") as file:
+    contents = file.read()           # reads a string from a file
+print(contents)
+# print: {"aa": 12, "bb": 21}
 
-with open('myfile2.txt', "r+") as file:
-    contents = json.load(file)       # reads a json object from a file
-print(contents)
-# print: {"aa": 12, "bb": 21}
+with open('myfile2.txt', "r+") as file:
+    contents = json.load(file)       # reads a json object from a file
+print(contents)
+# print: {"aa": 12, "bb": 21}
 
 
-# Python offers a fundamental abstraction called the Iterable.
-# An iterable is an object that can be treated as a sequence.
-# The object returned by the range function, is an iterable.
+# Python offers a fundamental abstraction called the Iterable.
+# An iterable is an object that can be treated as a sequence.
+# The object returned by the range function, is an iterable.
 
-filled_dict = {"one": 1, "two": 2, "three": 3}
+filled_dict = {"one": 1, "two": 2, "three": 3}
 our_iterable = filled_dict.keys()
-print(our_iterable)  # => dict_keys(['one', 'two', 'three']). This is an object that implements our Iterable interface.
+print(our_iterable)  # => dict_keys(['one', 'two', 'three']). This is an object
+                     # that implements our Iterable interface.
 
-# We can loop over it.
+# We can loop over it.
 for i in our_iterable:
-    print(i)  # Prints one, two, three
+    print(i)  # Prints one, two, three
 
-# However we cannot address elements by index.
-our_iterable[1]  # Raises a TypeError
+# However we cannot address elements by index.
+our_iterable[1]  # Raises a TypeError
 
-# An iterable is an object that knows how to create an iterator.
-our_iterator = iter(our_iterable)
+# An iterable is an object that knows how to create an iterator.
+our_iterator = iter(our_iterable)
 
-# Our iterator is an object that can remember the state as we traverse through it.
-# We get the next object with "next()".
-next(our_iterator)  # => "one"
+# Our iterator is an object that can remember the state as we traverse through
+# it. We get the next object with "next()".
+next(our_iterator)  # => "one"
 
-# It maintains state as we iterate.
-next(our_iterator)  # => "two"
-next(our_iterator)  # => "three"
+# It maintains state as we iterate.
+next(our_iterator)  # => "two"
+next(our_iterator)  # => "three"
 
-# After the iterator has returned all of its data, it raises a StopIteration exception
-next(our_iterator)  # Raises StopIteration
+# After the iterator has returned all of its data, it raises a
+# StopIteration exception
+next(our_iterator)  # Raises StopIteration
 
-# We can also loop over it, in fact, "for" does this implicitly!
-our_iterator = iter(our_iterable)
+# We can also loop over it, in fact, "for" does this implicitly!
+our_iterator = iter(our_iterable)
 for i in our_iterator:
-    print(i)  # Prints one, two, three
+    print(i)  # Prints one, two, three
 
-# You can grab all the elements of an iterable or iterator by calling list() on it.
-list(our_iterable)  # => Returns ["one", "two", "three"]
-list(our_iterator)  # => Returns [] because state is saved
+# You can grab all the elements of an iterable or iterator by call of list().
+list(our_iterable)  # => Returns ["one", "two", "three"]
+list(our_iterator)  # => Returns [] because state is saved
 
 
-####################################################
-## 4. Functions
-####################################################
+####################################################
+## 4. Functions
+####################################################
 
-# Use "def" to create new functions
-def add(x, y):
-    print("x is {} and y is {}".format(x, y))
-    return x + y  # Return values with a return statement
+# Use "def" to create new functions
+def add(x, y):
+    print("x is {} and y is {}".format(x, y))
+    return x + y  # Return values with a return statement
 
-# Calling functions with parameters
-add(5, 6)  # => prints out "x is 5 and y is 6" and returns 11
+# Calling functions with parameters
+add(5, 6)  # => prints out "x is 5 and y is 6" and returns 11
 
-# Another way to call functions is with keyword arguments
-add(y=6, x=5)  # Keyword arguments can arrive in any order.
+# Another way to call functions is with keyword arguments
+add(y=6, x=5)  # Keyword arguments can arrive in any order.
 
-# You can define functions that take a variable number of
-# positional arguments
-def varargs(*args):
+# You can define functions that take a variable number of
+# positional arguments
+def varargs(*args):
     return args
 
-varargs(1, 2, 3)  # => (1, 2, 3)
+varargs(1, 2, 3)  # => (1, 2, 3)
 
-# You can define functions that take a variable number of
-# keyword arguments, as well
-def keyword_args(**kwargs):
+# You can define functions that take a variable number of
+# keyword arguments, as well
+def keyword_args(**kwargs):
     return kwargs
 
-# Let's call it to see what happens
-keyword_args(big="foot", loch="ness")  # => {"big": "foot", "loch": "ness"}
+# Let's call it to see what happens
+keyword_args(big="foot", loch="ness")  # => {"big": "foot", "loch": "ness"}
 
 
-# You can do both at once, if you like
-def all_the_args(*args, **kwargs):
-    print(args)
-    print(kwargs)
+# You can do both at once, if you like
+def all_the_args(*args, **kwargs):
+    print(args)
+    print(kwargs)
 """
 all_the_args(1, 2, a=3, b=4) prints:
     (1, 2)
     {"a": 3, "b": 4}
 """
 
-# When calling functions, you can do the opposite of args/kwargs!
-# Use * to expand tuples and use ** to expand kwargs.
-args = (1, 2, 3, 4)
-kwargs = {"a": 3, "b": 4}
-all_the_args(*args)            # equivalent to all_the_args(1, 2, 3, 4)
-all_the_args(**kwargs)         # equivalent to all_the_args(a=3, b=4)
-all_the_args(*args, **kwargs)  # equivalent to all_the_args(1, 2, 3, 4, a=3, b=4)
-
-# Returning multiple values (with tuple assignments)
-def swap(x, y):
-    return y, x  # Return multiple values as a tuple without the parenthesis.
-                 # (Note: parenthesis have been excluded but can be included)
-
-x = 1
-y = 2
-x, y = swap(x, y)     # => x = 2, y = 1
-# (x, y) = swap(x,y)  # Again parenthesis have been excluded but can be included.
-
-# Function Scope
-x = 5
-
-def set_x(num):
-    # Local var x not the same as global variable x
-    x = num    # => 43
-    print(x)   # => 43
-
-def set_global_x(num):
+# When calling functions, you can do the opposite of args/kwargs!
+# Use * to expand tuples and use ** to expand kwargs.
+args = (1, 2, 3, 4)
+kwargs = {"a": 3, "b": 4}
+all_the_args(*args)            # equivalent: all_the_args(1, 2, 3, 4)
+all_the_args(**kwargs)         # equivalent: all_the_args(a=3, b=4)
+all_the_args(*args, **kwargs)  # equivalent: all_the_args(1, 2, 3, 4, a=3, b=4)
+
+# Returning multiple values (with tuple assignments)
+def swap(x, y):
+    return y, x  # Return multiple values as a tuple without the parenthesis.
+                 # (Note: parenthesis have been excluded but can be included)
+
+x = 1
+y = 2
+x, y = swap(x, y)     # => x = 2, y = 1
+# (x, y) = swap(x,y)  # Again the use of parenthesis is optional.
+
+# global scope
+x = 5
+
+def set_x(num):
+    # local scope begins here
+    # local var x not the same as global var x
+    x = num    # => 43
+    print(x)   # => 43
+
+def set_global_x(num):
+    # global indicates that particular var lives in the global scope
     global x
-    print(x)   # => 5
-    x = num    # global var x is now set to 6
-    print(x)   # => 6
+    print(x)   # => 5
+    x = num    # global var x is now set to 6
+    print(x)   # => 6
 
-set_x(43)
-set_global_x(6)
+set_x(43)
+set_global_x(6)
+"""
+prints:
+    43
+    5
+    6
+"""
 
 
-# Python has first class functions
-def create_adder(x):
-    def adder(y):
+# Python has first class functions
+def create_adder(x):
+    def adder(y):
         return x + y
     return adder
 
-add_10 = create_adder(10)
-add_10(3)   # => 13
+add_10 = create_adder(10)
+add_10(3)   # => 13
 
-# There are also anonymous functions
-(lambda x: x > 2)(3)                  # => True
-(lambda x, y: x ** 2 + y ** 2)(2, 1)  # => 5
+# There are also anonymous functions
+(lambda x: x > 2)(3)                  # => True
+(lambda x, y: x ** 2 + y ** 2)(2, 1)  # => 5
 
-# There are built-in higher order functions
-list(map(add_10, [1, 2, 3]))          # => [11, 12, 13]
-list(map(max, [1, 2, 3], [4, 2, 1]))  # => [4, 2, 3]
+# There are built-in higher order functions
+list(map(add_10, [1, 2, 3]))          # => [11, 12, 13]
+list(map(max, [1, 2, 3], [4, 2, 1]))  # => [4, 2, 3]
 
-list(filter(lambda x: x > 5, [3, 4, 5, 6, 7]))  # => [6, 7]
+list(filter(lambda x: x > 5, [3, 4, 5, 6, 7]))  # => [6, 7]
 
-# We can use list comprehensions for nice maps and filters
-# List comprehension stores the output as a list which can itself be a nested list
-[add_10(i) for i in [1, 2, 3]]         # => [11, 12, 13]
-[x for x in [3, 4, 5, 6, 7] if x > 5]  # => [6, 7]
+# We can use list comprehensions for nice maps and filters
+# List comprehension stores the output as a list (which itself may be nested).
+[add_10(i) for i in [1, 2, 3]]         # => [11, 12, 13]
+[x for x in [3, 4, 5, 6, 7] if x > 5]  # => [6, 7]
 
-# You can construct set and dict comprehensions as well.
-{x for x in 'abcddeef' if x not in 'abc'}  # => {'d', 'e', 'f'}
-{x: x**2 for x in range(5)}  # => {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
+# You can construct set and dict comprehensions as well.
+{x for x in 'abcddeef' if x not in 'abc'}  # => {'d', 'e', 'f'}
+{x: x**2 for x in range(5)}  # => {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
 
 
-####################################################
-## 5. Modules
-####################################################
+####################################################
+## 5. Modules
+####################################################
 
-# You can import modules
-import math
-print(math.sqrt(16))  # => 4.0
+# You can import modules
+import math
+print(math.sqrt(16))  # => 4.0
 
-# You can get specific functions from a module
-from math import ceil, floor
-print(ceil(3.7))   # => 4.0
-print(floor(3.7))  # => 3.0
+# You can get specific functions from a module
+from math import ceil, floor
+print(ceil(3.7))   # => 4.0
+print(floor(3.7))  # => 3.0
 
-# You can import all functions from a module.
-# Warning: this is not recommended
-from math import *
+# You can import all functions from a module.
+# Warning: this is not recommended
+from math import *
 
-# You can shorten module names
-import math as m
-math.sqrt(16) == m.sqrt(16)  # => True
+# You can shorten module names
+import math as m
+math.sqrt(16) == m.sqrt(16)  # => True
 
-# Python modules are just ordinary Python files. You
-# can write your own, and import them. The name of the
-# module is the same as the name of the file.
+# Python modules are just ordinary Python files. You
+# can write your own, and import them. The name of the
+# module is the same as the name of the file.
 
-# You can find out which functions and attributes
-# are defined in a module.
-import math
-dir(math)
+# You can find out which functions and attributes
+# are defined in a module.
+import math
+dir(math)
 
-# If you have a Python script named math.py in the same
-# folder as your current script, the file math.py will
-# be loaded instead of the built-in Python module.
-# This happens because the local folder has priority
-# over Python's built-in libraries.
+# If you have a Python script named math.py in the same
+# folder as your current script, the file math.py will
+# be loaded instead of the built-in Python module.
+# This happens because the local folder has priority
+# over Python's built-in libraries.
 
 
-####################################################
-## 6. Classes
-####################################################
+####################################################
+## 6. Classes
+####################################################
 
-# We use the "class" statement to create a class
-class Human:
+# We use the "class" statement to create a class
+class Human:
 
-    # A class attribute. It is shared by all instances of this class
+    # A class attribute. It is shared by all instances of this class
     species = "H. sapiens"
 
-    # Basic initializer, this is called when this class is instantiated.
-    # Note that the double leading and trailing underscores denote objects
-    # or attributes that are used by Python but that live in user-controlled
-    # namespaces. Methods(or objects or attributes) like: __init__, __str__,
-    # __repr__ etc. are called special methods (or sometimes called dunder methods)
-    # You should not invent such names on your own.
-    def __init__(self, name):
-        # Assign the argument to the instance's name attribute
-        self.name = name
-
-        # Initialize property
-        self._age = 0
-
-    # An instance method. All methods take "self" as the first argument
-    def say(self, msg):
-        print("{name}: {message}".format(name=self.name, message=msg))
-
-    # Another instance method
-    def sing(self):
+    # Basic initializer, this is called when this class is instantiated.
+    # Note that the double leading and trailing underscores denote objects
+    # or attributes that are used by Python but that live in user-controlled
+    # namespaces. Methods(or objects or attributes) like: __init__, __str__,
+    # __repr__ etc. are called special methods (or sometimes called dunder
+    # methods). You should not invent such names on your own.
+    def __init__(self, name):
+        # Assign the argument to the instance's name attribute
+        self.name = name
+
+        # Initialize property
+        self._age = 0
+
+    # An instance method. All methods take "self" as the first argument
+    def say(self, msg):
+        print("{name}: {message}".format(name=self.name, message=msg))
+
+    # Another instance method
+    def sing(self):
         return 'yo... yo... microphone check... one two... one two...'
 
-    # A class method is shared among all instances
-    # They are called with the calling class as the first argument
+    # A class method is shared among all instances
+    # They are called with the calling class as the first argument
     @classmethod
-    def get_species(cls):
-        return cls.species
+    def get_species(cls):
+        return cls.species
 
-    # A static method is called without a class or instance reference
+    # A static method is called without a class or instance reference
     @staticmethod
-    def grunt():
+    def grunt():
         return "*grunt*"
 
-    # A property is just like a getter.
-    # It turns the method age() into a read-only attribute of the same name.
-    # There's no need to write trivial getters and setters in Python, though.
+    # A property is just like a getter.
+    # It turns the method age() into a read-only attribute of the same name.
+    # There's no need to write trivial getters and setters in Python, though.
     @property
-    def age(self):
-        return self._age
+    def age(self):
+        return self._age
 
-    # This allows the property to be set
+    # This allows the property to be set
     @age.setter
-    def age(self, age):
-        self._age = age
+    def age(self, age):
+        self._age = age
 
-    # This allows the property to be deleted
+    # This allows the property to be deleted
     @age.deleter
-    def age(self):
-        del self._age
+    def age(self):
+        del self._age
 
 
-# When a Python interpreter reads a source file it executes all its code.
-# This __name__ check makes sure this code block is only executed when this
-# module is the main program.
+# When a Python interpreter reads a source file it executes all its code.
+# This __name__ check makes sure this code block is only executed when this
+# module is the main program.
 if __name__ == '__main__':
-    # Instantiate a class
+    # Instantiate a class
     i = Human(name="Ian")
-    i.say("hi")                     # "Ian: hi"
+    i.say("hi")                     # "Ian: hi"
     j = Human("Joel")
-    j.say("hello")                  # "Joel: hello"
-    # i and j are instances of type Human, or in other words: they are Human objects
+    j.say("hello")                  # "Joel: hello"
+    # i and j are instances of type Human; i.e., they are Human objects.
 
-    # Call our class method
-    i.say(i.get_species())          # "Ian: H. sapiens"
-    # Change the shared attribute
+    # Call our class method
+    i.say(i.get_species())          # "Ian: H. sapiens"
+    # Change the shared attribute
     Human.species = "H. neanderthalensis"
-    i.say(i.get_species())          # => "Ian: H. neanderthalensis"
-    j.say(j.get_species())          # => "Joel: H. neanderthalensis"
+    i.say(i.get_species())          # => "Ian: H. neanderthalensis"
+    j.say(j.get_species())          # => "Joel: H. neanderthalensis"
 
-    # Call the static method
-    print(Human.grunt())            # => "*grunt*"
+    # Call the static method
+    print(Human.grunt())            # => "*grunt*"
 
-    # Static methods can be called by instances too
-    print(i.grunt())                # => "*grunt*"
+    # Static methods can be called by instances too
+    print(i.grunt())                # => "*grunt*"
 
-    # Update the property for this instance
-    i.age = 42
-    # Get the property
-    i.say(i.age)                    # => "Ian: 42"
-    j.say(j.age)                    # => "Joel: 0"
-    # Delete the property
+    # Update the property for this instance
+    i.age = 42
+    # Get the property
+    i.say(i.age)                    # => "Ian: 42"
+    j.say(j.age)                    # => "Joel: 0"
+    # Delete the property
     del i.age
-    # i.age                         # => this would raise an AttributeError
+    # i.age                         # => this would raise an AttributeError
 
 
-####################################################
-## 6.1 Inheritance
-####################################################
+####################################################
+## 6.1 Inheritance
+####################################################
 
-# Inheritance allows new child classes to be defined that inherit methods and
-# variables from their parent class.
+# Inheritance allows new child classes to be defined that inherit methods and
+# variables from their parent class.
 
-# Using the Human class defined above as the base or parent class, we can
-# define a child class, Superhero, which inherits the class variables like
-# "species", "name", and "age", as well as methods, like "sing" and "grunt"
-# from the Human class, but can also have its own unique properties.
+# Using the Human class defined above as the base or parent class, we can
+# define a child class, Superhero, which inherits the class variables like
+# "species", "name", and "age", as well as methods, like "sing" and "grunt"
+# from the Human class, but can also have its own unique properties.
 
-# To take advantage of modularization by file you could place the classes above in their own files,
-# say, human.py
+# To take advantage of modularization by file you could place the classes above
+# in their own files, say, human.py
 
-# To import functions from other files use the following format
-# from "filename-without-extension" import "function-or-class"
+# To import functions from other files use the following format
+# from "filename-without-extension" import "function-or-class"
 
-from human import Human
+from human import Human
 
 
-# Specify the parent class(es) as parameters to the class definition
-class Superhero(Human):
+# Specify the parent class(es) as parameters to the class definition
+class Superhero(Human):
 
-    # If the child class should inherit all of the parent's definitions without
-    # any modifications, you can just use the "pass" keyword (and nothing else)
-    # but in this case it is commented out to allow for a unique child class:
-    # pass
+    # If the child class should inherit all of the parent's definitions without
+    # any modifications, you can just use the "pass" keyword (and nothing else)
+    # but in this case it is commented out to allow for a unique child class:
+    # pass
 
-    # Child classes can override their parents' attributes
+    # Child classes can override their parents' attributes
     species = 'Superhuman'
 
-    # Children automatically inherit their parent class's constructor including
-    # its arguments, but can also define additional arguments or definitions
-    # and override its methods such as the class constructor.
-    # This constructor inherits the "name" argument from the "Human" class and
-    # adds the "superpower" and "movie" arguments:
-    def __init__(self, name, movie=False,
+    # Children automatically inherit their parent class's constructor including
+    # its arguments, but can also define additional arguments or definitions
+    # and override its methods such as the class constructor.
+    # This constructor inherits the "name" argument from the "Human" class and
+    # adds the "superpower" and "movie" arguments:
+    def __init__(self, name, movie=False,
                  superpowers=["super strength", "bulletproofing"]):
 
-        # add additional class attributes:
-        self.fictional = True
-        self.movie = movie
-        # be aware of mutable default values, since defaults are shared
-        self.superpowers = superpowers
+        # add additional class attributes:
+        self.fictional = True
+        self.movie = movie
+        # be aware of mutable default values, since defaults are shared
+        self.superpowers = superpowers
 
-        # The "super" function lets you access the parent class's methods
-        # that are overridden by the child, in this case, the __init__ method.
-        # This calls the parent class constructor:
-        super().__init__(name)
+        # The "super" function lets you access the parent class's methods
+        # that are overridden by the child, in this case, the __init__ method.
+        # This calls the parent class constructor:
+        super().__init__(name)
 
-    # override the sing method
-    def sing(self):
+    # override the sing method
+    def sing(self):
         return 'Dun, dun, DUN!'
 
-    # add an additional instance method
-    def boast(self):
-        for power in self.superpowers:
-            print("I wield the power of {pow}!".format(pow=power))
+    # add an additional instance method
+    def boast(self):
+        for power in self.superpowers:
+            print("I wield the power of {pow}!".format(pow=power))
 
 
 if __name__ == '__main__':
     sup = Superhero(name="Tick")
 
-    # Instance type checks
-    if isinstance(sup, Human):
-        print('I am human')
-    if type(sup) is Superhero:
-        print('I am a superhero')
+    # Instance type checks
+    if isinstance(sup, Human):
+        print('I am human')
+    if type(sup) is Superhero:
+        print('I am a superhero')
 
-    # Get the Method Resolution search Order used by both getattr() and super()
-    # This attribute is dynamic and can be updated
-    print(Superhero.__mro__)    # => (<class '__main__.Superhero'>,
-                                # => <class 'human.Human'>, <class 'object'>)
+    # Get the Method Resolution search Order used by both getattr() and super()
+    # This attribute is dynamic and can be updated
+    print(Superhero.__mro__)    # => (<class '__main__.Superhero'>,
+                                # => <class 'human.Human'>, <class 'object'>)
 
-    # Calls parent method but uses its own class attribute
-    print(sup.get_species())    # => Superhuman
+    # Calls parent method but uses its own class attribute
+    print(sup.get_species())    # => Superhuman
 
-    # Calls overridden method
-    print(sup.sing())           # => Dun, dun, DUN!
+    # Calls overridden method
+    print(sup.sing())           # => Dun, dun, DUN!
 
-    # Calls method from Human
-    sup.say('Spoon')            # => Tick: Spoon
+    # Calls method from Human
+    sup.say('Spoon')            # => Tick: Spoon
 
-    # Call method that exists only in Superhero
-    sup.boast()                 # => I wield the power of super strength!
-                                # => I wield the power of bulletproofing!
+    # Call method that exists only in Superhero
+    sup.boast()                 # => I wield the power of super strength!
+                                # => I wield the power of bulletproofing!
 
-    # Inherited class attribute
-    sup.age = 31
-    print(sup.age)              # => 31
+    # Inherited class attribute
+    sup.age = 31
+    print(sup.age)              # => 31
 
-    # Attribute that only exists within Superhero
-    print('Am I Oscar eligible? ' + str(sup.movie))
+    # Attribute that only exists within Superhero
+    print('Am I Oscar eligible? ' + str(sup.movie))
 
-####################################################
-## 6.2 Multiple Inheritance
-####################################################
+####################################################
+## 6.2 Multiple Inheritance
+####################################################
 
-# Another class definition
-# bat.py
-class Bat:
+# Another class definition
+# bat.py
+class Bat:
 
     species = 'Baty'
 
-    def __init__(self, can_fly=True):
-        self.fly = can_fly
+    def __init__(self, can_fly=True):
+        self.fly = can_fly
 
-    # This class also has a say method
-    def say(self, msg):
+    # This class also has a say method
+    def say(self, msg):
         msg = '... ... ...'
         return msg
 
-    # And its own method as well
-    def sonar(self):
+    # And its own method as well
+    def sonar(self):
         return '))) ... ((('
 
 if __name__ == '__main__':
     b = Bat()
-    print(b.say('hello'))
-    print(b.fly)
-
-
-# And yet another class definition that inherits from Superhero and Bat
-# superhero.py
-from superhero import Superhero
-from bat import Bat
-
-# Define Batman as a child that inherits from both Superhero and Bat
-class Batman(Superhero, Bat):
-
-    def __init__(self, *args, **kwargs):
-        # Typically to inherit attributes you have to call super:
-        # super(Batman, self).__init__(*args, **kwargs)
-        # However we are dealing with multiple inheritance here, and super()
-        # only works with the next base class in the MRO list.
-        # So instead we explicitly call __init__ for all ancestors.
-        # The use of *args and **kwargs allows for a clean way to pass arguments,
-        # with each parent "peeling a layer of the onion".
-        Superhero.__init__(self, 'anonymous', movie=True,
+    print(b.say('hello'))
+    print(b.fly)
+
+
+# And yet another class definition that inherits from Superhero and Bat
+# superhero.py
+from superhero import Superhero
+from bat import Bat
+
+# Define Batman as a child that inherits from both Superhero and Bat
+class Batman(Superhero, Bat):
+
+    def __init__(self, *args, **kwargs):
+        # Typically to inherit attributes you have to call super:
+        # super(Batman, self).__init__(*args, **kwargs)
+        # However we are dealing with multiple inheritance here, and super()
+        # only works with the next base class in the MRO list.
+        # So instead we explicitly call __init__ for all ancestors.
+        # The use of *args and **kwargs allows for a clean way to pass
+        # arguments, with each parent "peeling a layer of the onion".
+        Superhero.__init__(self, 'anonymous', movie=True,
                            superpowers=['Wealthy'], *args, **kwargs)
-        Bat.__init__(self, *args, can_fly=False, **kwargs)
-        # override the value for the name attribute
-        self.name = 'Sad Affleck'
+        Bat.__init__(self, *args, can_fly=False, **kwargs)
+        # override the value for the name attribute
+        self.name = 'Sad Affleck'
 
-    def sing(self):
+    def sing(self):
         return 'nan nan nan nan nan batman!'
 
 
 if __name__ == '__main__':
     sup = Batman()
 
-    # Get the Method Resolution search Order used by both getattr() and super().
-    # This attribute is dynamic and can be updated
-    print(Batman.__mro__)       # => (<class '__main__.Batman'>,
-                                # => <class 'superhero.Superhero'>,
-                                # => <class 'human.Human'>,
-                                # => <class 'bat.Bat'>, <class 'object'>)
+    # Get the Method Resolution search Order used by both getattr() and super().
+    # This attribute is dynamic and can be updated
+    print(Batman.__mro__)       # => (<class '__main__.Batman'>,
+                                # => <class 'superhero.Superhero'>,
+                                # => <class 'human.Human'>,
+                                # => <class 'bat.Bat'>, <class 'object'>)
 
-    # Calls parent method but uses its own class attribute
-    print(sup.get_species())    # => Superhuman
+    # Calls parent method but uses its own class attribute
+    print(sup.get_species())    # => Superhuman
 
-    # Calls overridden method
-    print(sup.sing())           # => nan nan nan nan nan batman!
+    # Calls overridden method
+    print(sup.sing())           # => nan nan nan nan nan batman!
 
-    # Calls method from Human, because inheritance order matters
-    sup.say('I agree')          # => Sad Affleck: I agree
+    # Calls method from Human, because inheritance order matters
+    sup.say('I agree')          # => Sad Affleck: I agree
 
-    # Call method that exists only in 2nd ancestor
-    print(sup.sonar())          # => ))) ... (((
+    # Call method that exists only in 2nd ancestor
+    print(sup.sonar())          # => ))) ... (((
 
-    # Inherited class attribute
-    sup.age = 100
-    print(sup.age)              # => 100
+    # Inherited class attribute
+    sup.age = 100
+    print(sup.age)              # => 100
 
-    # Inherited attribute from 2nd ancestor whose default value was overridden.
-    print('Can I fly? ' + str(sup.fly)) # => Can I fly? False
+    # Inherited attribute from 2nd ancestor whose default value was overridden.
+    print('Can I fly? ' + str(sup.fly)) # => Can I fly? False
 
 
 
-####################################################
-## 7. Advanced
-####################################################
+####################################################
+## 7. Advanced
+####################################################
 
-# Generators help you make lazy code.
-def double_numbers(iterable):
+# Generators help you make lazy code.
+def double_numbers(iterable):
     for i in iterable:
         yield i + i
 
-# Generators are memory-efficient because they only load the data needed to
-# process the next value in the iterable. This allows them to perform
-# operations on otherwise prohibitively large value ranges.
-# NOTE: `range` replaces `xrange` in Python 3.
-for i in double_numbers(range(1, 900000000)):  # `range` is a generator.
-    print(i)
-    if i >= 30:
+# Generators are memory-efficient because they only load the data needed to
+# process the next value in the iterable. This allows them to perform
+# operations on otherwise prohibitively large value ranges.
+# NOTE: `range` replaces `xrange` in Python 3.
+for i in double_numbers(range(1, 900000000)):  # `range` is a generator.
+    print(i)
+    if i >= 30:
         break
 
-# Just as you can create a list comprehension, you can create generator
-# comprehensions as well.
-values = (-x for x in [1,2,3,4,5])
+# Just as you can create a list comprehension, you can create generator
+# comprehensions as well.
+values = (-x for x in [1,2,3,4,5])
 for x in values:
-    print(x)  # prints -1 -2 -3 -4 -5 to console/terminal
+    print(x)  # prints -1 -2 -3 -4 -5 to console/terminal
 
-# You can also cast a generator comprehension directly to a list.
-values = (-x for x in [1,2,3,4,5])
-gen_to_list = list(values)
-print(gen_to_list)  # => [-1, -2, -3, -4, -5]
+# You can also cast a generator comprehension directly to a list.
+values = (-x for x in [1,2,3,4,5])
+gen_to_list = list(values)
+print(gen_to_list)  # => [-1, -2, -3, -4, -5]
 
 
-# Decorators
-# In this example `beg` wraps `say`. If say_please is True then it
-# will change the returned message.
-from functools import wraps
+# Decorators
+# In this example `beg` wraps `say`. If say_please is True then it
+# will change the returned message.
+from functools import wraps
 
 
-def beg(target_function):
+def beg(target_function):
     @wraps(target_function)
-    def wrapper(*args, **kwargs):
+    def wrapper(*args, **kwargs):
         msg, say_please = target_function(*args, **kwargs)
         if say_please:
             return "{} {}".format(msg, "Please! I am poor :(")
@@ -992,10 +1008,10 @@
 
 
 @beg
-def say(say_please=False):
+def say(say_please=False):
     msg = "Can you buy me a beer?"
     return msg, say_please
 
 
-print(say())                 # Can you buy me a beer?
-print(say(say_please=True))  # Can you buy me a beer? Please! I am poor :(
+print(say())                 # Can you buy me a beer?
+print(say(say_please=True))  # Can you buy me a beer? Please! I am poor :(
diff --git a/tests/results/16 b/tests/results/16
index b653ffd5..263cd83a 100644
--- a/tests/results/16
+++ b/tests/results/16
@@ -2,15 +2,15 @@
 
 1ns                          Main memory reference:       Send 2,000 bytes             Read 1,000,000 bytes         
 ▗▖                           100ns                        over commodity network:      sequentially from SSD:       
-                             ▗▖                           31ns                         38.876us                     
+                             ▗▖                           15ns                         24.49us                      
 L1 cache reference: 1ns                                   ▗                            ▗                            
 ▗▖                           1.0us                                                                                  
-                             ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         SSD random read: 16.0us      Disk seek: 2.332582ms        
+                             ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         SSD random read: 16.0us      Disk seek: 2.03063ms         
 Branch mispredict: 3ns                                    ▗▖▗                          ▗▖▗▖                         
 ▗▖▗▖▗▖                                                                                                              
                              Compress 1KB wth Snappy:     Read 1,000,000 bytes         Read 1,000,000 bytes         
 L2 cache reference: 4ns      2.0us                        sequentially from memory:    sequentially from disk:      
-▗▖▗▖▗▖▗▖                     ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         2.355us                      717.936us                    
+▗▖▗▖▗▖▗▖                     ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         1.483us                      544.094us                    
                              ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗                            ▗                            
 Mutex lock/unlock: 16ns                                                                                             
 ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      Round trip                   Packet roundtrip             
diff --git a/tests/results/17 b/tests/results/17
index 6fb087ff..a5b95b92 100644
--- a/tests/results/17
+++ b/tests/results/17
@@ -1,120 +1,120 @@
  cheat.sheets:az 
-# Microsoft Azure CLI 2.0
-# Command-line tools for Azure
+# Microsoft Azure CLI 2.0
+# Command-line tools for Azure
 
-# Install Azure CLI 2.0 with one curl command.
-curl -L https://aka.ms/InstallAzureCli | bash
+# Install Azure CLI 2.0 with one curl command.
+curl -L https://aka.ms/InstallAzureCli | bash
 
-# create a resource group named "MyRG" in the 'westus2' region
-az group create -n MyRG -l westus2
+# create a resource group named "MyRG" in the 'westus2' region
+az group create -n MyRG -l westus2
 
-# create a Linux VM using the UbuntuTLS image,
-# with two attached storage disks of 10 GB and 20 GB
-az vm create -n MyLinuxVM -g MyRG \
-    --ssh-key-value $HOME/.ssh/id_rsa.pub --image UbuntuLTS \
-    --data-disk-sizes-gb 10 20
+# create a Linux VM using the UbuntuTLS image,
+# with two attached storage disks of 10 GB and 20 GB
+az vm create -n MyLinuxVM -g MyRG \
+    --ssh-key-value $HOME/.ssh/id_rsa.pub --image UbuntuLTS \
+    --data-disk-sizes-gb 10 20
 
-# list VMs
-az vm list --output table
+# list VMs
+az vm list --output table
 
-# list only VMs having distinct state
-az vm list -d --query "[?powerState=='VM running']" --output table
+# list only VMs having distinct state
+az vm list -d --query "[?powerState=='VM running']" --output table
 
-# delete VM (with the name MyLinuxVM in the group MyRG)
-az vm delete -g MyRG -n MyLinuxVM --yes
+# delete VM (with the name MyLinuxVM in the group MyRG)
+az vm delete -g MyRG -n MyLinuxVM --yes
 
-# Delete all VMs in a resource group
-az vm delete --ids $(az vm list -g MyRG --query "[].id" -o tsv)
+# Delete all VMs in a resource group
+az vm delete --ids $(az vm list -g MyRG --query "[].id" -o tsv)
 
-# Create an Image based on a running VM
-az vm deallocate -g MyRG -n MyLinuxVM
-az vm generalize -g MyRG -n MyLinuxVM
-az image create --resource-group MyRG --name MyTestImage --source MyLinuxVM
+# Create an Image based on a running VM
+az vm deallocate -g MyRG -n MyLinuxVM
+az vm generalize -g MyRG -n MyLinuxVM
+az image create --resource-group MyRG --name MyTestImage --source MyLinuxVM
 
-# Running VM based on a VHD
-az storage blob upload --account-name "${account_name}"  \
-   --account-key "${account_key}" --container-name "${container}" --type page \
-   --file "${file}" --name "${vhd}"
-az disk create \
-   --resource-group "${resource_group}" \
-   --name myManagedDisk \
-   --source "https://${account_name}.blob.core.windows.net/${container}/${vhd}"
+# Running VM based on a VHD
+az storage blob upload --account-name "${account_name}"  \
+   --account-key "${account_key}" --container-name "${container}" --type page \
+   --file "${file}" --name "${vhd}"
+az disk create \
+   --resource-group "${resource_group}" \
+   --name myManagedDisk \
+   --source "https://${account_name}.blob.core.windows.net/${container}/${vhd}"
 
-# open port
-az vm open-port --resource-group MyRG --name MyLinuxVM --port 443 --priority 899
+# open port
+az vm open-port --resource-group MyRG --name MyLinuxVM --port 443 --priority 899
 
-# Show storage accounts
-az storage account list --output table
+# Show storage accounts
+az storage account list --output table
 
-# Show containers for an account
-az storage container list --account-name mystorageaccount --output table
+# Show containers for an account
+az storage container list --account-name mystorageaccount --output table
 
-# Show blobs in a container
-az storage blob list --account-name mystorageaccount \
-    --container-name mycontainer  --output table
+# Show blobs in a container
+az storage blob list --account-name mystorageaccount \
+    --container-name mycontainer  --output table
 
-# list account keys
-az storage account keys list  --account-name STORAGE_NAME --resource-group RESOURCE_GROUP
+# list account keys
+az storage account keys list  --account-name STORAGE_NAME --resource-group RESOURCE_GROUP
 
-# Show own images
-az image list --output table
+# Show own images
+az image list --output table
 
-# Configure default storage location
-az configure --defaults location=eastus2
+# Configure default storage location
+az configure --defaults location=eastus2
 
-# Show disks
-az disk list --output table
+# Show disks
+az disk list --output table
 
-# Copy blob
-az storage blob copy start \
-    --source-uri 'https://xxx.blob.core.windows.net/jzwuuuzzapn0/abcd?...' \
-    --account-key XXXXXXXXXX== \
-    --account-name destaccount \
-    --destination-container vms \
-    --destination-blob DESTINATION-blob.vhd
+# Copy blob
+az storage blob copy start \
+    --source-uri 'https://xxx.blob.core.windows.net/jzwuuuzzapn0/abcd?...' \
+    --account-key XXXXXXXXXX== \
+    --account-name destaccount \
+    --destination-container vms \
+    --destination-blob DESTINATION-blob.vhd
 
-# List virtual networks
-az network vnet list --output table
+# List virtual networks
+az network vnet list --output table
 
-# List virtual networks adapters
-az network nic list --output table
+# List virtual networks adapters
+az network nic list --output table
 
-# List public IP addresses used by the VMs
-az vm list-ip-addresses --output table
+# List public IP addresses used by the VMs
+az vm list-ip-addresses --output table
 
-# create snapshot
-az snapshot create --resource-group IC-EXASOL-001 --source vm1-disk1 -n vm1-snap1
+# create snapshot
+az snapshot create --resource-group IC-EXASOL-001 --source vm1-disk1 -n vm1-snap1
 
-# create SAS url for a snapshot
-az snapshot grant-access --resource-group IC-EXASOL-001 --name vm1-snap1\
-    --duration-in-seconds 36000 --query '[accessSas]' -o tsv
+# create SAS url for a snapshot
+az snapshot grant-access --resource-group IC-EXASOL-001 --name vm1-snap1\
+    --duration-in-seconds 36000 --query '[accessSas]' -o tsv
 
-# attach disk
-az vm disk attach --vm-name vm1 -g RESOURCE_GROUP --disk DISK1_ID
+# attach disk
+az vm disk attach --vm-name vm1 -g RESOURCE_GROUP --disk DISK1_ID
 
-# detach disk
-az vm disk detach --vm-name vm1 -g RESOURCE_GROUP --name DISK1_ID
+# detach disk
+az vm disk detach --vm-name vm1 -g RESOURCE_GROUP --name DISK1_ID
 
  tldr:az 
-# az
-# The official CLI tool for Microsoft Azure.
-# Some subcommands such as `az login` have their own usage documentation.
-# More information: <https://docs.microsoft.com/cli/azure>.
+# az
+# The official CLI tool for Microsoft Azure.
+# Some subcommands such as `az login` have their own usage documentation.
+# More information: <https://learn.microsoft.com/cli/azure>.
 
-# Log in to Azure:
-az login
+# Log in to Azure:
+az login
 
-# Manage azure subscription information:
-az account
+# Manage azure subscription information:
+az account
 
-# List all Azure Managed Disks:
-az disk list
+# List all Azure Managed Disks:
+az disk list
 
-# List all Azure virtual machines:
-az vm list
+# List all Azure virtual machines:
+az vm list
 
-# Manage Azure Kubernetes Services:
-az aks
+# Manage Azure Kubernetes Services:
+az aks
 
-# Manage Azure Network resources:
-az network
+# Manage Azure Network resources:
+az network
diff --git a/tests/results/18 b/tests/results/18
index 651c8c08..279a2ef9 100644
--- a/tests/results/18
+++ b/tests/results/18
@@ -1,19 +1,19 @@
 >>> s = 'abcdefgh'
->>> n, m, char, chars = 2, 3, 'd', 'cd'
->>> # starting from n=2 characters in and m=3 in length;
->>> s[n-1:n+m-1]
+>>> n, m, char, chars = 2, 3, 'd', 'cd'
+>>> # starting from n=2 characters in and m=3 in length;
+>>> s[n-1:n+m-1]
 'bcd'
->>> # starting from n characters in, up to the end of the string;
->>> s[n-1:]
+>>> # starting from n characters in, up to the end of the string;
+>>> s[n-1:]
 'bcdefgh'
->>> # whole string minus last character;
->>> s[:-1]
+>>> # whole string minus last character;
+>>> s[:-1]
 'abcdefg'
->>> # starting from a known character char="d" within the string and of m length;
+>>> # starting from a known character char="d" within the string and of m length;
 >>> indx = s.index(char)
 >>> s[indx:indx+m]
 'def'
->>> # starting from a known substring chars="cd" within the string and of m length.
+>>> # starting from a known substring chars="cd" within the string and of m length.
 >>> indx = s.index(chars)
 >>> s[indx:indx+m]
 'cde'
diff --git a/tests/results/2 b/tests/results/2
index 3d5b767b..530d74b6 100644
--- a/tests/results/2
+++ b/tests/results/2
@@ -1,47 +1,63 @@
  cheat:ls 
-# To display everything in <dir>, excluding hidden files:
-ls <dir>
+# To display everything in <dir>, excluding hidden files:
+ls <dir>
 
-# To display everything in <dir>, including hidden files:
-ls -a <dir>
+# To display everything in <dir>, including hidden files:
+ls -a <dir>
 
-# To display all files, along with the size (with unit suffixes) and timestamp
-ls -lh <dir>
+# To display all files, along with the size (with unit suffixes) and timestamp:
+ls -lh <dir>
 
-# To display files, sorted by size:
-ls -S <dir>
+# To display files, sorted by size:
+ls -S <dir>
 
-# To display directories only:
-ls -d */ <dir>
+# To display directories only:
+ls -d */ <dir>
 
-# To display directories only, include hidden:
-ls -d .*/ */ <dir>
+# To display directories only, include hidden:
+ls -d .*/ */ <dir>
+
+# To display all files sorted by changed date, most recent first:
+ls -ltc 
+
+# To display files sorted by create time:
+ls -lt
+
+# To display files in a single column:
+ls -1
+
+# To show ACLs (MacOS):
+# see also `cheat chmod` for `/bin/chmod` options for ACLs
+/bin/ls -le
+
+# To show all the subtree files (Recursive Mode):
+ls -R
 
  tldr:ls 
-# ls
-# List directory contents.
-# More information: <https://www.gnu.org/software/coreutils/ls>.
+# ls
+# List directory contents.
+# More information: <https://www.gnu.org/software/coreutils/ls>.
 
-# List files one per line:
-ls -1
+# List files one per line:
+ls -1
 
-# List all files, including hidden files:
-ls -a
+# List all files, including hidden files:
+ls -a
 
-# List all files, with trailing `/` added to directory names:
-ls -F
+# List all files, with trailing `/` added to directory names:
+ls -F
 
-# Long format list (permissions, ownership, size, and modification date) of all files:
-ls -la
+# Long format list (permissions, ownership, size, and modification date) of all files:
+ls -la
 
-# Long format list with size displayed using human-readable units (KiB, MiB, GiB):
-ls -lh
+# Long format list with size displayed using human-readable units (KiB, MiB, GiB):
+ls -lh
 
-# Long format list sorted by size (descending):
-ls -lS
+# Long format list sorted by size (descending):
+ls -lS
 
-# Long format list of all files, sorted by modification date (oldest first):
-ls -ltr
+# Long format list of all files, sorted by modification date (oldest first):
+ls -ltr
 
-# Only list directories:
-ls -d */
+# Only list directories:
+ls -d */
diff --git a/tests/results/21 b/tests/results/21
index bfd13d39..6dd970d0 100644
--- a/tests/results/21
+++ b/tests/results/21
@@ -1,606 +1,606 @@
-// Single-line comments start with two slashes.
-/* Multiline comments start with slash-star,
-   and end with star-slash */
+// Single-line comments start with two slashes.
+/* Multiline comments start with slash-star,
+   and end with star-slash */
 
-// Statements can be terminated by ;
+// Statements can be terminated by ;
 doStuff();
 
-// ... but they don't have to be, as semicolons are automatically inserted
-// wherever there's a newline, except in certain cases.
+// ... but they don't have to be, as semicolons are automatically inserted
+// wherever there's a newline, except in certain cases.
 doStuff()
 
-// Because those cases can cause unexpected results, we'll keep on using
-// semicolons in this guide.
+// Because those cases can cause unexpected results, we'll keep on using
+// semicolons in this guide.
 
-///////////////////////////////////
-// 1. Numbers, Strings and Operators
+///////////////////////////////////
+// 1. Numbers, Strings and Operators
 
-// JavaScript has one number type (which is a 64-bit IEEE 754 double).
-// Doubles have a 52-bit mantissa, which is enough to store integers
-// up to about 9✕10¹⁵ precisely.
-3; // = 3
-1.5; // = 1.5
+// JavaScript has one number type (which is a 64-bit IEEE 754 double).
+// Doubles have a 52-bit mantissa, which is enough to store integers
+// up to about 9✕10¹⁵ precisely.
+3; // = 3
+1.5; // = 1.5
 
-// Some basic arithmetic works as you'd expect.
-1 + 1; // = 2
-0.1 + 0.2; // = 0.30000000000000004
-8 - 1; // = 7
-10 * 2; // = 20
-35 / 5; // = 7
+// Some basic arithmetic works as you'd expect.
+1 + 1; // = 2
+0.1 + 0.2; // = 0.30000000000000004
+8 - 1; // = 7
+10 * 2; // = 20
+35 / 5; // = 7
 
-// Including uneven division.
-5 / 2; // = 2.5
+// Including uneven division.
+5 / 2; // = 2.5
 
-// And modulo division.
-10 % 2; // = 0
-30 % 4; // = 2
-18.5 % 7; // = 4.5
+// And modulo division.
+10 % 2; // = 0
+30 % 4; // = 2
+18.5 % 7; // = 4.5
 
-// Bitwise operations also work; when you perform a bitwise operation your float
-// is converted to a signed int *up to* 32 bits.
-1 << 2; // = 4
+// Bitwise operations also work; when you perform a bitwise operation your float
+// is converted to a signed int *up to* 32 bits.
+1 << 2; // = 4
 
-// Precedence is enforced with parentheses.
-(1 + 3) * 2; // = 8
+// Precedence is enforced with parentheses.
+(1 + 3) * 2; // = 8
 
-// There are three special not-a-real-number values:
-Infinity; // result of e.g. 1/0
--Infinity; // result of e.g. -1/0
-NaN; // result of e.g. 0/0, stands for 'Not a Number'
+// There are three special not-a-real-number values:
+Infinity; // result of e.g. 1/0
+-Infinity; // result of e.g. -1/0
+NaN; // result of e.g. 0/0, stands for 'Not a Number'
 
-// There's also a boolean type.
+// There's also a boolean type.
 true;
 false;
 
-// Strings are created with ' or ".
+// Strings are created with ' or ".
 'abc';
 "Hello, world";
 
-// Negation uses the ! symbol
-!true; // = false
-!false; // = true
+// Negation uses the ! symbol
+!true; // = false
+!false; // = true
 
-// Equality is ===
-1 === 1; // = true
-2 === 1; // = false
+// Equality is ===
+1 === 1; // = true
+2 === 1; // = false
 
-// Inequality is !==
-1 !== 1; // = false
-2 !== 1; // = true
+// Inequality is !==
+1 !== 1; // = false
+2 !== 1; // = true
 
-// More comparisons
-1 < 10; // = true
-1 > 10; // = false
-2 <= 2; // = true
-2 >= 2; // = true
+// More comparisons
+1 < 10; // = true
+1 > 10; // = false
+2 <= 2; // = true
+2 >= 2; // = true
 
-// Strings are concatenated with +
-"Hello " + "world!"; // = "Hello world!"
+// Strings are concatenated with +
+"Hello " + "world!"; // = "Hello world!"
 
-// ... which works with more than just strings
-"1, 2, " + 3; // = "1, 2, 3"
-"Hello " + ["world", "!"]; // = "Hello world,!"
+// ... which works with more than just strings
+"1, 2, " + 3; // = "1, 2, 3"
+"Hello " + ["world", "!"]; // = "Hello world,!"
 
-// and are compared with < and >
-"a" < "b"; // = true
+// and are compared with < and >
+"a" < "b"; // = true
 
-// Type coercion is performed for comparisons with double equals...
-"5" == 5; // = true
-null == undefined; // = true
+// Type coercion is performed for comparisons with double equals...
+"5" == 5; // = true
+null == undefined; // = true
 
-// ...unless you use ===
-"5" === 5; // = false
-null === undefined; // = false
+// ...unless you use ===
+"5" === 5; // = false
+null === undefined; // = false
 
-// ...which can result in some weird behaviour...
-13 + !0; // 14
-"13" + !0; // '13true'
+// ...which can result in some weird behaviour...
+13 + !0; // 14
+"13" + !0; // '13true'
 
-// You can access characters in a string with `charAt`
-"This is a string".charAt(0);  // = 'T'
+// You can access characters in a string with `charAt`
+"This is a string".charAt(0);  // = 'T'
 
-// ...or use `substring` to get larger pieces.
-"Hello world".substring(0, 5); // = "Hello"
+// ...or use `substring` to get larger pieces.
+"Hello world".substring(0, 5); // = "Hello"
 
-// `length` is a property, so don't use ().
-"Hello".length; // = 5
+// `length` is a property, so don't use ().
+"Hello".length; // = 5
 
-// There's also `null` and `undefined`.
-null;      // used to indicate a deliberate non-value
-undefined; // used to indicate a value is not currently present (although
-           // `undefined` is actually a value itself)
+// There's also `null` and `undefined`.
+null;      // used to indicate a deliberate non-value
+undefined; // used to indicate a value is not currently present (although
+           // `undefined` is actually a value itself)
 
-// false, null, undefined, NaN, 0 and "" are falsy; everything else is truthy.
-// Note that 0 is falsy and "0" is truthy, even though 0 == "0".
+// false, null, undefined, NaN, 0 and "" are falsy; everything else is truthy.
+// Note that 0 is falsy and "0" is truthy, even though 0 == "0".
 
-///////////////////////////////////
-// 2. Variables, Arrays and Objects
+///////////////////////////////////
+// 2. Variables, Arrays and Objects
 
-// Variables are declared with the `var` keyword. JavaScript is dynamically
-// typed, so you don't need to specify type. Assignment uses a single `=`
-// character.
-var someVar = 5;
+// Variables are declared with the `var` keyword. JavaScript is dynamically
+// typed, so you don't need to specify type. Assignment uses a single `=`
+// character.
+var someVar = 5;
 
-// If you leave the var keyword off, you won't get an error...
-someOtherVar = 10;
+// If you leave the var keyword off, you won't get an error...
+someOtherVar = 10;
 
-// ...but your variable will be created in the global scope, not in the scope
-// you defined it in.
+// ...but your variable will be created in the global scope, not in the scope
+// you defined it in.
 
-// Variables declared without being assigned to are set to undefined.
-var someThirdVar; // = undefined
+// Variables declared without being assigned to are set to undefined.
+var someThirdVar; // = undefined
 
-// If you want to declare a couple of variables, then you could use a comma
-// separator
-var someFourthVar = 2, someFifthVar = 4;
+// If you want to declare a couple of variables, then you could use a comma
+// separator
+var someFourthVar = 2, someFifthVar = 4;
 
-// There's shorthand for performing math operations on variables:
-someVar += 5; // equivalent to someVar = someVar + 5; someVar is 10 now
-someVar *= 10; // now someVar is 100
+// There's shorthand for performing math operations on variables:
+someVar += 5; // equivalent to someVar = someVar + 5; someVar is 10 now
+someVar *= 10; // now someVar is 100
 
-// and an even-shorter-hand for adding or subtracting 1
-someVar++; // now someVar is 101
-someVar--; // back to 100
+// and an even-shorter-hand for adding or subtracting 1
+someVar++; // now someVar is 101
+someVar--; // back to 100
 
-// Arrays are ordered lists of values, of any type.
-var myArray = ["Hello", 45, true];
+// Arrays are ordered lists of values, of any type.
+var myArray = ["Hello", 45, true];
 
-// Their members can be accessed using the square-brackets subscript syntax.
-// Array indices start at zero.
-myArray[1]; // = 45
+// Their members can be accessed using the square-brackets subscript syntax.
+// Array indices start at zero.
+myArray[1]; // = 45
 
-// Arrays are mutable and of variable length.
+// Arrays are mutable and of variable length.
 myArray.push("World");
-myArray.length; // = 4
+myArray.length; // = 4
 
-// Add/Modify at specific index
-myArray[3] = "Hello";
+// Add/Modify at specific index
+myArray[3] = "Hello";
 
-// Add and remove element from front or back end of an array
-myArray.unshift(3); // Add as the first element
-someVar = myArray.shift(); // Remove first element and return it
-myArray.push(3); // Add as the last element
-someVar = myArray.pop(); // Remove last element and return it
+// Add and remove element from front or back end of an array
+myArray.unshift(3); // Add as the first element
+someVar = myArray.shift(); // Remove first element and return it
+myArray.push(3); // Add as the last element
+someVar = myArray.pop(); // Remove last element and return it
 
-// Join all elements of an array with semicolon
-var myArray0 = [32,false,"js",12,56,90];
-myArray0.join(";"); // = "32;false;js;12;56;90"
+// Join all elements of an array with semicolon
+var myArray0 = [32,false,"js",12,56,90];
+myArray0.join(";"); // = "32;false;js;12;56;90"
 
-// Get subarray of elements from index 1 (include) to 4 (exclude)
-myArray0.slice(1,4); // = [false,"js",12]
+// Get subarray of elements from index 1 (include) to 4 (exclude)
+myArray0.slice(1,4); // = [false,"js",12]
 
-// Remove 4 elements starting from index 2, and insert there strings
-// "hi","wr" and "ld"; return removed subarray
-myArray0.splice(2,4,"hi","wr","ld"); // = ["js",12,56,90]
-// myArray0 === [32,false,"hi","wr","ld"]
+// Remove 4 elements starting from index 2, and insert there strings
+// "hi","wr" and "ld"; return removed subarray
+myArray0.splice(2,4,"hi","wr","ld"); // = ["js",12,56,90]
+// myArray0 === [32,false,"hi","wr","ld"]
 
-// JavaScript's objects are equivalent to "dictionaries" or "maps" in other
-// languages: an unordered collection of key-value pairs.
-var myObj = {key1: "Hello", key2: "World"};
+// JavaScript's objects are equivalent to "dictionaries" or "maps" in other
+// languages: an unordered collection of key-value pairs.
+var myObj = {key1: "Hello", key2: "World"};
 
-// Keys are strings, but quotes aren't required if they're a valid
-// JavaScript identifier. Values can be any type.
-var myObj = {myKey: "myValue", "my other key": 4};
+// Keys are strings, but quotes aren't required if they're a valid
+// JavaScript identifier. Values can be any type.
+var myObj = {myKey: "myValue", "my other key": 4};
 
-// Object attributes can also be accessed using the subscript syntax,
-myObj["my other key"]; // = 4
+// Object attributes can also be accessed using the subscript syntax,
+myObj["my other key"]; // = 4
 
-// ... or using the dot syntax, provided the key is a valid identifier.
-myObj.myKey; // = "myValue"
+// ... or using the dot syntax, provided the key is a valid identifier.
+myObj.myKey; // = "myValue"
 
-// Objects are mutable; values can be changed and new keys added.
-myObj.myThirdKey = true;
+// Objects are mutable; values can be changed and new keys added.
+myObj.myThirdKey = true;
 
-// If you try to access a value that's not yet set, you'll get undefined.
-myObj.myFourthKey; // = undefined
+// If you try to access a value that's not yet set, you'll get undefined.
+myObj.myFourthKey; // = undefined
 
-///////////////////////////////////
-// 3. Logic and Control Structures
+///////////////////////////////////
+// 3. Logic and Control Structures
 
-// The `if` structure works as you'd expect.
-var count = 1;
-if (count == 3){
-    // evaluated if count is 3
-} else if (count == 4){
-    // evaluated if count is 4
-} else {
-    // evaluated if it's not either 3 or 4
+// The `if` structure works as you'd expect.
+var count = 1;
+if (count == 3){
+    // evaluated if count is 3
+} else if (count == 4){
+    // evaluated if count is 4
+} else {
+    // evaluated if it's not either 3 or 4
 }
 
-// As does `while`.
-while (true){
-    // An infinite loop!
+// As does `while`.
+while (true){
+    // An infinite loop!
 }
 
-// Do-while loops are like while loops, except they always run at least once.
-var input;
-do {
-    input = getInput();
-} while (!isValid(input));
+// Do-while loops are like while loops, except they always run at least once.
+var input;
+do {
+    input = getInput();
+} while (!isValid(input));
 
-// The `for` loop is the same as C and Java:
-// initialization; continue condition; iteration.
-for (var i = 0; i < 5; i++){
-    // will run 5 times
+// The `for` loop is the same as C and Java:
+// initialization; continue condition; iteration.
+for (var i = 0; i < 5; i++){
+    // will run 5 times
 }
 
-// Breaking out of labeled loops is similar to Java
+// Breaking out of labeled loops is similar to Java
 outer:
-for (var i = 0; i < 10; i++) {
-    for (var j = 0; j < 10; j++) {
-        if (i == 5 && j ==5) {
-            break outer;
-            // breaks out of outer loop instead of only the inner one
-        }
-    }
+for (var i = 0; i < 10; i++) {
+    for (var j = 0; j < 10; j++) {
+        if (i == 5 && j ==5) {
+            break outer;
+            // breaks out of outer loop instead of only the inner one
+        }
+    }
 }
 
-// The for/in statement allows iteration over properties of an object.
-var description = "";
-var person = {fname:"Paul", lname:"Ken", age:18};
-for (var x in person){
-    description += person[x] + " ";
-} // description = 'Paul Ken 18 '
-
-// The for/of statement allows iteration over iterable objects (including the built-in String, 
-// Array, e.g. the Array-like arguments or NodeList objects, TypedArray, Map and Set, 
-// and user-defined iterables).
-var myPets = "";
-var pets = ["cat", "dog", "hamster", "hedgehog"];
-for (var pet of pets){
-    myPets += pet + " ";
-} // myPets = 'cat dog hamster hedgehog '
-
-// && is logical and, || is logical or
-if (house.size == "big" && house.colour == "blue"){
-    house.contains = "bear";
+// The for/in statement allows iteration over properties of an object.
+var description = "";
+var person = {fname:"Paul", lname:"Ken", age:18};
+for (var x in person){
+    description += person[x] + " ";
+} // description = 'Paul Ken 18 '
+
+// The for/of statement allows iteration over iterable objects (including the built-in String, 
+// Array, e.g. the Array-like arguments or NodeList objects, TypedArray, Map and Set, 
+// and user-defined iterables).
+var myPets = "";
+var pets = ["cat", "dog", "hamster", "hedgehog"];
+for (var pet of pets){
+    myPets += pet + " ";
+} // myPets = 'cat dog hamster hedgehog '
+
+// && is logical and, || is logical or
+if (house.size == "big" && house.colour == "blue"){
+    house.contains = "bear";
 }
-if (colour == "red" || colour == "blue"){
-    // colour is either red or blue
+if (colour == "red" || colour == "blue"){
+    // colour is either red or blue
 }
 
-// && and || "short circuit", which is useful for setting default values.
-var name = otherName || "default";
-
-// The `switch` statement checks for equality with `===`.
-// Use 'break' after each case
-// or the cases after the correct one will be executed too.
-grade = 'B';
-switch (grade) {
-  case 'A':
-    console.log("Great job");
-    break;
-  case 'B':
-    console.log("OK job");
-    break;
-  case 'C':
-    console.log("You can do better");
-    break;
-  default:
-    console.log("Oy vey");
-    break;
+// && and || "short circuit", which is useful for setting default values.
+var name = otherName || "default";
+
+// The `switch` statement checks for equality with `===`.
+// Use 'break' after each case
+// or the cases after the correct one will be executed too.
+grade = 'B';
+switch (grade) {
+  case 'A':
+    console.log("Great job");
+    break;
+  case 'B':
+    console.log("OK job");
+    break;
+  case 'C':
+    console.log("You can do better");
+    break;
+  default:
+    console.log("Oy vey");
+    break;
 }
 
 
-///////////////////////////////////
-// 4. Functions, Scope and Closures
+///////////////////////////////////
+// 4. Functions, Scope and Closures
 
-// JavaScript functions are declared with the `function` keyword.
-function myFunction(thing){
-    return thing.toUpperCase();
+// JavaScript functions are declared with the `function` keyword.
+function myFunction(thing){
+    return thing.toUpperCase();
 }
-myFunction("foo"); // = "FOO"
-
-// Note that the value to be returned must start on the same line as the
-// `return` keyword, otherwise you'll always return `undefined` due to
-// automatic semicolon insertion. Watch out for this when using Allman style.
-function myFunction(){
-    return // <- semicolon automatically inserted here
-    {thisIsAn: 'object literal'};
+myFunction("foo"); // = "FOO"
+
+// Note that the value to be returned must start on the same line as the
+// `return` keyword, otherwise you'll always return `undefined` due to
+// automatic semicolon insertion. Watch out for this when using Allman style.
+function myFunction(){
+    return // <- semicolon automatically inserted here
+    {thisIsAn: 'object literal'};
 }
-myFunction(); // = undefined
+myFunction(); // = undefined
 
-// JavaScript functions are first class objects, so they can be reassigned to
-// different variable names and passed to other functions as arguments - for
-// example, when supplying an event handler:
-function myFunction(){
-    // this code will be called in 5 seconds' time
+// JavaScript functions are first class objects, so they can be reassigned to
+// different variable names and passed to other functions as arguments - for
+// example, when supplying an event handler:
+function myFunction(){
+    // this code will be called in 5 seconds' time
 }
-setTimeout(myFunction, 5000);
-// Note: setTimeout isn't part of the JS language, but is provided by browsers
-// and Node.js.
+setTimeout(myFunction, 5000);
+// Note: setTimeout isn't part of the JS language, but is provided by browsers
+// and Node.js.
 
-// Another function provided by browsers is setInterval
-function myFunction(){
-    // this code will be called every 5 seconds
+// Another function provided by browsers is setInterval
+function myFunction(){
+    // this code will be called every 5 seconds
 }
-setInterval(myFunction, 5000);
+setInterval(myFunction, 5000);
 
-// Function objects don't even have to be declared with a name - you can write
-// an anonymous function definition directly into the arguments of another.
+// Function objects don't even have to be declared with a name - you can write
+// an anonymous function definition directly into the arguments of another.
 setTimeout(function(){
-    // this code will be called in 5 seconds' time
-}, 5000);
+    // this code will be called in 5 seconds' time
+}, 5000);
 
-// JavaScript has function scope; functions get their own scope but other blocks
-// do not.
-if (true){
-    var i = 5;
+// JavaScript has function scope; functions get their own scope but other blocks
+// do not.
+if (true){
+    var i = 5;
 }
-i; // = 5 - not undefined as you'd expect in a block-scoped language
+i; // = 5 - not undefined as you'd expect in a block-scoped language
 
-// This has led to a common pattern of "immediately-executing anonymous
-// functions", which prevent temporary variables from leaking into the global
-// scope.
+// This has led to a common pattern of "immediately-executing anonymous
+// functions", which prevent temporary variables from leaking into the global
+// scope.
 (function(){
-    var temporary = 5;
-    // We can access the global scope by assigning to the "global object", which
-    // in a web browser is always `window`. The global object may have a
-    // different name in non-browser environments such as Node.js.
-    window.permanent = 10;
+    var temporary = 5;
+    // We can access the global scope by assigning to the "global object", which
+    // in a web browser is always `window`. The global object may have a
+    // different name in non-browser environments such as Node.js.
+    window.permanent = 10;
 })();
-temporary; // raises ReferenceError
-permanent; // = 10
-
-// One of JavaScript's most powerful features is closures. If a function is
-// defined inside another function, the inner function has access to all the
-// outer function's variables, even after the outer function exits.
-function sayHelloInFiveSeconds(name){
-    var prompt = "Hello, " + name + "!";
-    // Inner functions are put in the local scope by default, as if they were
-    // declared with `var`.
-    function inner(){
-        alert(prompt);
-    }
-    setTimeout(inner, 5000);
-    // setTimeout is asynchronous, so the sayHelloInFiveSeconds function will
-    // exit immediately, and setTimeout will call inner afterwards. However,
-    // because inner is "closed over" sayHelloInFiveSeconds, inner still has
-    // access to the `prompt` variable when it is finally called.
+temporary; // raises ReferenceError
+permanent; // = 10
+
+// One of JavaScript's most powerful features is closures. If a function is
+// defined inside another function, the inner function has access to all the
+// outer function's variables, even after the outer function exits.
+function sayHelloInFiveSeconds(name){
+    var prompt = "Hello, " + name + "!";
+    // Inner functions are put in the local scope by default, as if they were
+    // declared with `var`.
+    function inner(){
+        alert(prompt);
+    }
+    setTimeout(inner, 5000);
+    // setTimeout is asynchronous, so the sayHelloInFiveSeconds function will
+    // exit immediately, and setTimeout will call inner afterwards. However,
+    // because inner is "closed over" sayHelloInFiveSeconds, inner still has
+    // access to the `prompt` variable when it is finally called.
 }
-sayHelloInFiveSeconds("Adam"); // will open a popup with "Hello, Adam!" in 5s
+sayHelloInFiveSeconds("Adam"); // will open a popup with "Hello, Adam!" in 5s
 
-///////////////////////////////////
-// 5. More about Objects; Constructors and Prototypes
+///////////////////////////////////
+// 5. More about Objects; Constructors and Prototypes
 
-// Objects can contain functions.
-var myObj = {
-    myFunc: function(){
-        return "Hello world!";
-    }
+// Objects can contain functions.
+var myObj = {
+    myFunc: function(){
+        return "Hello world!";
+    }
 };
-myObj.myFunc(); // = "Hello world!"
-
-// When functions attached to an object are called, they can access the object
-// they're attached to using the `this` keyword.
-myObj = {
-    myString: "Hello world!",
-    myFunc: function(){
-        return this.myString;
-    }
+myObj.myFunc(); // = "Hello world!"
+
+// When functions attached to an object are called, they can access the object
+// they're attached to using the `this` keyword.
+myObj = {
+    myString: "Hello world!",
+    myFunc: function(){
+        return this.myString;
+    }
 };
-myObj.myFunc(); // = "Hello world!"
-
-// What this is set to has to do with how the function is called, not where
-// it's defined. So, our function doesn't work if it isn't called in the
-// context of the object.
-var myFunc = myObj.myFunc;
-myFunc(); // = undefined
-
-// Inversely, a function can be assigned to the object and gain access to it
-// through `this`, even if it wasn't attached when it was defined.
-var myOtherFunc = function(){
-    return this.myString.toUpperCase();
+myObj.myFunc(); // = "Hello world!"
+
+// What this is set to has to do with how the function is called, not where
+// it's defined. So, our function doesn't work if it isn't called in the
+// context of the object.
+var myFunc = myObj.myFunc;
+myFunc(); // = undefined
+
+// Inversely, a function can be assigned to the object and gain access to it
+// through `this`, even if it wasn't attached when it was defined.
+var myOtherFunc = function(){
+    return this.myString.toUpperCase();
 };
-myObj.myOtherFunc = myOtherFunc;
-myObj.myOtherFunc(); // = "HELLO WORLD!"
+myObj.myOtherFunc = myOtherFunc;
+myObj.myOtherFunc(); // = "HELLO WORLD!"
 
-// We can also specify a context for a function to execute in when we invoke it
-// using `call` or `apply`.
+// We can also specify a context for a function to execute in when we invoke it
+// using `call` or `apply`.
 
-var anotherFunc = function(s){
-    return this.myString + s;
+var anotherFunc = function(s){
+    return this.myString + s;
 };
-anotherFunc.call(myObj, " And Hello Moon!"); // = "Hello World! And Hello Moon!"
+anotherFunc.call(myObj, " And Hello Moon!"); // = "Hello World! And Hello Moon!"
 
-// The `apply` function is nearly identical, but takes an array for an argument
-// list.
+// The `apply` function is nearly identical, but takes an array for an argument
+// list.
 
-anotherFunc.apply(myObj, [" And Hello Sun!"]); // = "Hello World! And Hello Sun!"
+anotherFunc.apply(myObj, [" And Hello Sun!"]); // = "Hello World! And Hello Sun!"
 
-// This is useful when working with a function that accepts a sequence of
-// arguments and you want to pass an array.
+// This is useful when working with a function that accepts a sequence of
+// arguments and you want to pass an array.
 
-Math.min(42, 6, 27); // = 6
-Math.min([42, 6, 27]); // = NaN (uh-oh!)
-Math.min.apply(Math, [42, 6, 27]); // = 6
+Math.min(42, 6, 27); // = 6
+Math.min([42, 6, 27]); // = NaN (uh-oh!)
+Math.min.apply(Math, [42, 6, 27]); // = 6
 
-// But, `call` and `apply` are only temporary. When we want it to stick, we can
-// use `bind`.
+// But, `call` and `apply` are only temporary. When we want it to stick, we can
+// use `bind`.
 
-var boundFunc = anotherFunc.bind(myObj);
-boundFunc(" And Hello Saturn!"); // = "Hello World! And Hello Saturn!"
+var boundFunc = anotherFunc.bind(myObj);
+boundFunc(" And Hello Saturn!"); // = "Hello World! And Hello Saturn!"
 
-// `bind` can also be used to partially apply (curry) a function.
+// `bind` can also be used to partially apply (curry) a function.
 
-var product = function(a, b){ return a * b; };
-var doubler = product.bind(this, 2);
-doubler(8); // = 16
+var product = function(a, b){ return a * b; };
+var doubler = product.bind(this, 2);
+doubler(8); // = 16
 
-// When you call a function with the `new` keyword, a new object is created, and
-// made available to the function via the `this` keyword. Functions designed to be
-// called like that are called constructors.
+// When you call a function with the `new` keyword, a new object is created, and
+// made available to the function via the `this` keyword. Functions designed to be
+// called like that are called constructors.
 
-var MyConstructor = function(){
-    this.myNumber = 5;
+var MyConstructor = function(){
+    this.myNumber = 5;
 };
-myNewObj = new MyConstructor(); // = {myNumber: 5}
-myNewObj.myNumber; // = 5
-
-// Unlike most other popular object-oriented languages, JavaScript has no
-// concept of 'instances' created from 'class' blueprints; instead, JavaScript
-// combines instantiation and inheritance into a single concept: a 'prototype'.
-
-// Every JavaScript object has a 'prototype'. When you go to access a property
-// on an object that doesn't exist on the actual object, the interpreter will
-// look at its prototype.
-
-// Some JS implementations let you access an object's prototype on the magic
-// property `__proto__`. While this is useful for explaining prototypes it's not
-// part of the standard; we'll get to standard ways of using prototypes later.
-var myObj = {
-    myString: "Hello world!"
+myNewObj = new MyConstructor(); // = {myNumber: 5}
+myNewObj.myNumber; // = 5
+
+// Unlike most other popular object-oriented languages, JavaScript has no
+// concept of 'instances' created from 'class' blueprints; instead, JavaScript
+// combines instantiation and inheritance into a single concept: a 'prototype'.
+
+// Every JavaScript object has a 'prototype'. When you go to access a property
+// on an object that doesn't exist on the actual object, the interpreter will
+// look at its prototype.
+
+// Some JS implementations let you access an object's prototype on the magic
+// property `__proto__`. While this is useful for explaining prototypes it's not
+// part of the standard; we'll get to standard ways of using prototypes later.
+var myObj = {
+    myString: "Hello world!"
 };
-var myPrototype = {
-    meaningOfLife: 42,
-    myFunc: function(){
-        return this.myString.toLowerCase();
-    }
+var myPrototype = {
+    meaningOfLife: 42,
+    myFunc: function(){
+        return this.myString.toLowerCase();
+    }
 };
 
-myObj.__proto__ = myPrototype;
-myObj.meaningOfLife; // = 42
+myObj.__proto__ = myPrototype;
+myObj.meaningOfLife; // = 42
 
-// This works for functions, too.
-myObj.myFunc(); // = "hello world!"
+// This works for functions, too.
+myObj.myFunc(); // = "hello world!"
 
-// Of course, if your property isn't on your prototype, the prototype's
-// prototype is searched, and so on.
-myPrototype.__proto__ = {
-    myBoolean: true
+// Of course, if your property isn't on your prototype, the prototype's
+// prototype is searched, and so on.
+myPrototype.__proto__ = {
+    myBoolean: true
 };
-myObj.myBoolean; // = true
-
-// There's no copying involved here; each object stores a reference to its
-// prototype. This means we can alter the prototype and our changes will be
-// reflected everywhere.
-myPrototype.meaningOfLife = 43;
-myObj.meaningOfLife; // = 43
-
-// The for/in statement allows iteration over properties of an object,
-// walking up the prototype chain until it sees a null prototype.
-for (var x in myObj){
-    console.log(myObj[x]);
+myObj.myBoolean; // = true
+
+// There's no copying involved here; each object stores a reference to its
+// prototype. This means we can alter the prototype and our changes will be
+// reflected everywhere.
+myPrototype.meaningOfLife = 43;
+myObj.meaningOfLife; // = 43
+
+// The for/in statement allows iteration over properties of an object,
+// walking up the prototype chain until it sees a null prototype.
+for (var x in myObj){
+    console.log(myObj[x]);
 }
-///prints:
-// Hello world!
-// 43
-// [Function: myFunc]
-// true
-
-// To only consider properties attached to the object itself
-// and not its prototypes, use the `hasOwnProperty()` check.
-for (var x in myObj){
-    if (myObj.hasOwnProperty(x)){
-        console.log(myObj[x]);
-    }
+///prints:
+// Hello world!
+// 43
+// [Function: myFunc]
+// true
+
+// To only consider properties attached to the object itself
+// and not its prototypes, use the `hasOwnProperty()` check.
+for (var x in myObj){
+    if (myObj.hasOwnProperty(x)){
+        console.log(myObj[x]);
+    }
 }
-///prints:
-// Hello world!
-
-// We mentioned that `__proto__` was non-standard, and there's no standard way to
-// change the prototype of an existing object. However, there are two ways to
-// create a new object with a given prototype.
-
-// The first is Object.create, which is a recent addition to JS, and therefore
-// not available in all implementations yet.
-var myObj = Object.create(myPrototype);
-myObj.meaningOfLife; // = 43
-
-// The second way, which works anywhere, has to do with constructors.
-// Constructors have a property called prototype. This is *not* the prototype of
-// the constructor function itself; instead, it's the prototype that new objects
-// are given when they're created with that constructor and the new keyword.
-MyConstructor.prototype = {
-    myNumber: 5,
-    getMyNumber: function(){
-        return this.myNumber;
-    }
+///prints:
+// Hello world!
+
+// We mentioned that `__proto__` was non-standard, and there's no standard way to
+// change the prototype of an existing object. However, there are two ways to
+// create a new object with a given prototype.
+
+// The first is Object.create, which is a recent addition to JS, and therefore
+// not available in all implementations yet.
+var myObj = Object.create(myPrototype);
+myObj.meaningOfLife; // = 43
+
+// The second way, which works anywhere, has to do with constructors.
+// Constructors have a property called prototype. This is *not* the prototype of
+// the constructor function itself; instead, it's the prototype that new objects
+// are given when they're created with that constructor and the new keyword.
+MyConstructor.prototype = {
+    myNumber: 5,
+    getMyNumber: function(){
+        return this.myNumber;
+    }
 };
-var myNewObj2 = new MyConstructor();
-myNewObj2.getMyNumber(); // = 5
-myNewObj2.myNumber = 6;
-myNewObj2.getMyNumber(); // = 6
-
-// Built-in types like strings and numbers also have constructors that create
-// equivalent wrapper objects.
-var myNumber = 12;
-var myNumberObj = new Number(12);
-myNumber == myNumberObj; // = true
-
-// Except, they aren't exactly equivalent.
-typeof myNumber; // = 'number'
-typeof myNumberObj; // = 'object'
-myNumber === myNumberObj; // = false
-if (0){
-    // This code won't execute, because 0 is falsy.
+var myNewObj2 = new MyConstructor();
+myNewObj2.getMyNumber(); // = 5
+myNewObj2.myNumber = 6;
+myNewObj2.getMyNumber(); // = 6
+
+// Built-in types like strings and numbers also have constructors that create
+// equivalent wrapper objects.
+var myNumber = 12;
+var myNumberObj = new Number(12);
+myNumber == myNumberObj; // = true
+
+// Except, they aren't exactly equivalent.
+typeof myNumber; // = 'number'
+typeof myNumberObj; // = 'object'
+myNumber === myNumberObj; // = false
+if (0){
+    // This code won't execute, because 0 is falsy.
 }
-if (new Number(0)){
-   // This code will execute, because wrapped numbers are objects, and objects
-   // are always truthy.
+if (new Number(0)){
+   // This code will execute, because wrapped numbers are objects, and objects
+   // are always truthy.
 }
 
-// However, the wrapper objects and the regular builtins share a prototype, so
-// you can actually add functionality to a string, for instance.
-String.prototype.firstCharacter = function(){
-    return this.charAt(0);
+// However, the wrapper objects and the regular builtins share a prototype, so
+// you can actually add functionality to a string, for instance.
+String.prototype.firstCharacter = function(){
+    return this.charAt(0);
 };
-"abc".firstCharacter(); // = "a"
-
-// This fact is often used in "polyfilling", which is implementing newer
-// features of JavaScript in an older subset of JavaScript, so that they can be
-// used in older environments such as outdated browsers.
-
-// For instance, we mentioned that Object.create isn't yet available in all
-// implementations, but we can still use it with this polyfill:
-if (Object.create === undefined){ // don't overwrite it if it exists
-    Object.create = function(proto){
-        // make a temporary constructor with the right prototype
-        var Constructor = function(){};
-        Constructor.prototype = proto;
-        // then use it to create a new, appropriately-prototyped object
-        return new Constructor();
-    };
+"abc".firstCharacter(); // = "a"
+
+// This fact is often used in "polyfilling", which is implementing newer
+// features of JavaScript in an older subset of JavaScript, so that they can be
+// used in older environments such as outdated browsers.
+
+// For instance, we mentioned that Object.create isn't yet available in all
+// implementations, but we can still use it with this polyfill:
+if (Object.create === undefined){ // don't overwrite it if it exists
+    Object.create = function(proto){
+        // make a temporary constructor with the right prototype
+        var Constructor = function(){};
+        Constructor.prototype = proto;
+        // then use it to create a new, appropriately-prototyped object
+        return new Constructor();
+    };
 }
 
-// ES6 Additions
+// ES6 Additions
 
-// The "let" keyword allows you to define variables in a lexical scope, 
-// as opposed to a block scope like the var keyword does.
-let name = "Billy";
+// The "let" keyword allows you to define variables in a lexical scope, 
+// as opposed to a function scope like the var keyword does.
+let name = "Billy";
 
-// Variables defined with let can be reassigned new values.
-name = "William";
+// Variables defined with let can be reassigned new values.
+name = "William";
 
-// The "const" keyword allows you to define a variable in a lexical scope
-// like with let, but you cannot reassign the value once one has been assigned.
+// The "const" keyword allows you to define a variable in a lexical scope
+// like with let, but you cannot reassign the value once one has been assigned.
 
-const pi = 3.14;
+const pi = 3.14;
 
-pi = 4.13; // You cannot do this.
+pi = 4.13; // You cannot do this.
 
-// There is a new syntax for functions in ES6 known as "lambda syntax".
-// This allows functions to be defined in a lexical scope like with variables
-// defined by const and let. 
+// There is a new syntax for functions in ES6 known as "lambda syntax".
+// This allows functions to be defined in a lexical scope like with variables
+// defined by const and let. 
 
-const isEven = (number) => {
-    return number % 2 === 0;
+const isEven = (number) => {
+    return number % 2 === 0;
 };
 
-isEven(7); // false
+isEven(7); // false
 
-// The "equivalent" of this function in the traditional syntax would look like this:
+// The "equivalent" of this function in the traditional syntax would look like this:
 
-function isEven(number) {
-    return number % 2 === 0;
+function isEven(number) {
+    return number % 2 === 0;
 };
 
-// I put the word "equivalent" in double quotes because a function defined
-// using the lambda syntax cannnot be called before the definition.
-// The following is an example of invalid usage:
+// I put the word "equivalent" in double quotes because a function defined
+// using the lambda syntax cannot be called before the definition.
+// The following is an example of invalid usage:
 
-add(1, 8);
+add(1, 8);
 
-const add = (firstNumber, secondNumber) => {
-    return firstNumber + secondNumber;
+const add = (firstNumber, secondNumber) => {
+    return firstNumber + secondNumber;
 };
diff --git a/tests/results/22 b/tests/results/22
index bfd13d39..6dd970d0 100644
--- a/tests/results/22
+++ b/tests/results/22
@@ -1,606 +1,606 @@
-// Single-line comments start with two slashes.
-/* Multiline comments start with slash-star,
-   and end with star-slash */
+// Single-line comments start with two slashes.
+/* Multiline comments start with slash-star,
+   and end with star-slash */
 
-// Statements can be terminated by ;
+// Statements can be terminated by ;
 doStuff();
 
-// ... but they don't have to be, as semicolons are automatically inserted
-// wherever there's a newline, except in certain cases.
+// ... but they don't have to be, as semicolons are automatically inserted
+// wherever there's a newline, except in certain cases.
 doStuff()
 
-// Because those cases can cause unexpected results, we'll keep on using
-// semicolons in this guide.
+// Because those cases can cause unexpected results, we'll keep on using
+// semicolons in this guide.
 
-///////////////////////////////////
-// 1. Numbers, Strings and Operators
+///////////////////////////////////
+// 1. Numbers, Strings and Operators
 
-// JavaScript has one number type (which is a 64-bit IEEE 754 double).
-// Doubles have a 52-bit mantissa, which is enough to store integers
-// up to about 9✕10¹⁵ precisely.
-3; // = 3
-1.5; // = 1.5
+// JavaScript has one number type (which is a 64-bit IEEE 754 double).
+// Doubles have a 52-bit mantissa, which is enough to store integers
+// up to about 9✕10¹⁵ precisely.
+3; // = 3
+1.5; // = 1.5
 
-// Some basic arithmetic works as you'd expect.
-1 + 1; // = 2
-0.1 + 0.2; // = 0.30000000000000004
-8 - 1; // = 7
-10 * 2; // = 20
-35 / 5; // = 7
+// Some basic arithmetic works as you'd expect.
+1 + 1; // = 2
+0.1 + 0.2; // = 0.30000000000000004
+8 - 1; // = 7
+10 * 2; // = 20
+35 / 5; // = 7
 
-// Including uneven division.
-5 / 2; // = 2.5
+// Including uneven division.
+5 / 2; // = 2.5
 
-// And modulo division.
-10 % 2; // = 0
-30 % 4; // = 2
-18.5 % 7; // = 4.5
+// And modulo division.
+10 % 2; // = 0
+30 % 4; // = 2
+18.5 % 7; // = 4.5
 
-// Bitwise operations also work; when you perform a bitwise operation your float
-// is converted to a signed int *up to* 32 bits.
-1 << 2; // = 4
+// Bitwise operations also work; when you perform a bitwise operation your float
+// is converted to a signed int *up to* 32 bits.
+1 << 2; // = 4
 
-// Precedence is enforced with parentheses.
-(1 + 3) * 2; // = 8
+// Precedence is enforced with parentheses.
+(1 + 3) * 2; // = 8
 
-// There are three special not-a-real-number values:
-Infinity; // result of e.g. 1/0
--Infinity; // result of e.g. -1/0
-NaN; // result of e.g. 0/0, stands for 'Not a Number'
+// There are three special not-a-real-number values:
+Infinity; // result of e.g. 1/0
+-Infinity; // result of e.g. -1/0
+NaN; // result of e.g. 0/0, stands for 'Not a Number'
 
-// There's also a boolean type.
+// There's also a boolean type.
 true;
 false;
 
-// Strings are created with ' or ".
+// Strings are created with ' or ".
 'abc';
 "Hello, world";
 
-// Negation uses the ! symbol
-!true; // = false
-!false; // = true
+// Negation uses the ! symbol
+!true; // = false
+!false; // = true
 
-// Equality is ===
-1 === 1; // = true
-2 === 1; // = false
+// Equality is ===
+1 === 1; // = true
+2 === 1; // = false
 
-// Inequality is !==
-1 !== 1; // = false
-2 !== 1; // = true
+// Inequality is !==
+1 !== 1; // = false
+2 !== 1; // = true
 
-// More comparisons
-1 < 10; // = true
-1 > 10; // = false
-2 <= 2; // = true
-2 >= 2; // = true
+// More comparisons
+1 < 10; // = true
+1 > 10; // = false
+2 <= 2; // = true
+2 >= 2; // = true
 
-// Strings are concatenated with +
-"Hello " + "world!"; // = "Hello world!"
+// Strings are concatenated with +
+"Hello " + "world!"; // = "Hello world!"
 
-// ... which works with more than just strings
-"1, 2, " + 3; // = "1, 2, 3"
-"Hello " + ["world", "!"]; // = "Hello world,!"
+// ... which works with more than just strings
+"1, 2, " + 3; // = "1, 2, 3"
+"Hello " + ["world", "!"]; // = "Hello world,!"
 
-// and are compared with < and >
-"a" < "b"; // = true
+// and are compared with < and >
+"a" < "b"; // = true
 
-// Type coercion is performed for comparisons with double equals...
-"5" == 5; // = true
-null == undefined; // = true
+// Type coercion is performed for comparisons with double equals...
+"5" == 5; // = true
+null == undefined; // = true
 
-// ...unless you use ===
-"5" === 5; // = false
-null === undefined; // = false
+// ...unless you use ===
+"5" === 5; // = false
+null === undefined; // = false
 
-// ...which can result in some weird behaviour...
-13 + !0; // 14
-"13" + !0; // '13true'
+// ...which can result in some weird behaviour...
+13 + !0; // 14
+"13" + !0; // '13true'
 
-// You can access characters in a string with `charAt`
-"This is a string".charAt(0);  // = 'T'
+// You can access characters in a string with `charAt`
+"This is a string".charAt(0);  // = 'T'
 
-// ...or use `substring` to get larger pieces.
-"Hello world".substring(0, 5); // = "Hello"
+// ...or use `substring` to get larger pieces.
+"Hello world".substring(0, 5); // = "Hello"
 
-// `length` is a property, so don't use ().
-"Hello".length; // = 5
+// `length` is a property, so don't use ().
+"Hello".length; // = 5
 
-// There's also `null` and `undefined`.
-null;      // used to indicate a deliberate non-value
-undefined; // used to indicate a value is not currently present (although
-           // `undefined` is actually a value itself)
+// There's also `null` and `undefined`.
+null;      // used to indicate a deliberate non-value
+undefined; // used to indicate a value is not currently present (although
+           // `undefined` is actually a value itself)
 
-// false, null, undefined, NaN, 0 and "" are falsy; everything else is truthy.
-// Note that 0 is falsy and "0" is truthy, even though 0 == "0".
+// false, null, undefined, NaN, 0 and "" are falsy; everything else is truthy.
+// Note that 0 is falsy and "0" is truthy, even though 0 == "0".
 
-///////////////////////////////////
-// 2. Variables, Arrays and Objects
+///////////////////////////////////
+// 2. Variables, Arrays and Objects
 
-// Variables are declared with the `var` keyword. JavaScript is dynamically
-// typed, so you don't need to specify type. Assignment uses a single `=`
-// character.
-var someVar = 5;
+// Variables are declared with the `var` keyword. JavaScript is dynamically
+// typed, so you don't need to specify type. Assignment uses a single `=`
+// character.
+var someVar = 5;
 
-// If you leave the var keyword off, you won't get an error...
-someOtherVar = 10;
+// If you leave the var keyword off, you won't get an error...
+someOtherVar = 10;
 
-// ...but your variable will be created in the global scope, not in the scope
-// you defined it in.
+// ...but your variable will be created in the global scope, not in the scope
+// you defined it in.
 
-// Variables declared without being assigned to are set to undefined.
-var someThirdVar; // = undefined
+// Variables declared without being assigned to are set to undefined.
+var someThirdVar; // = undefined
 
-// If you want to declare a couple of variables, then you could use a comma
-// separator
-var someFourthVar = 2, someFifthVar = 4;
+// If you want to declare a couple of variables, then you could use a comma
+// separator
+var someFourthVar = 2, someFifthVar = 4;
 
-// There's shorthand for performing math operations on variables:
-someVar += 5; // equivalent to someVar = someVar + 5; someVar is 10 now
-someVar *= 10; // now someVar is 100
+// There's shorthand for performing math operations on variables:
+someVar += 5; // equivalent to someVar = someVar + 5; someVar is 10 now
+someVar *= 10; // now someVar is 100
 
-// and an even-shorter-hand for adding or subtracting 1
-someVar++; // now someVar is 101
-someVar--; // back to 100
+// and an even-shorter-hand for adding or subtracting 1
+someVar++; // now someVar is 101
+someVar--; // back to 100
 
-// Arrays are ordered lists of values, of any type.
-var myArray = ["Hello", 45, true];
+// Arrays are ordered lists of values, of any type.
+var myArray = ["Hello", 45, true];
 
-// Their members can be accessed using the square-brackets subscript syntax.
-// Array indices start at zero.
-myArray[1]; // = 45
+// Their members can be accessed using the square-brackets subscript syntax.
+// Array indices start at zero.
+myArray[1]; // = 45
 
-// Arrays are mutable and of variable length.
+// Arrays are mutable and of variable length.
 myArray.push("World");
-myArray.length; // = 4
+myArray.length; // = 4
 
-// Add/Modify at specific index
-myArray[3] = "Hello";
+// Add/Modify at specific index
+myArray[3] = "Hello";
 
-// Add and remove element from front or back end of an array
-myArray.unshift(3); // Add as the first element
-someVar = myArray.shift(); // Remove first element and return it
-myArray.push(3); // Add as the last element
-someVar = myArray.pop(); // Remove last element and return it
+// Add and remove element from front or back end of an array
+myArray.unshift(3); // Add as the first element
+someVar = myArray.shift(); // Remove first element and return it
+myArray.push(3); // Add as the last element
+someVar = myArray.pop(); // Remove last element and return it
 
-// Join all elements of an array with semicolon
-var myArray0 = [32,false,"js",12,56,90];
-myArray0.join(";"); // = "32;false;js;12;56;90"
+// Join all elements of an array with semicolon
+var myArray0 = [32,false,"js",12,56,90];
+myArray0.join(";"); // = "32;false;js;12;56;90"
 
-// Get subarray of elements from index 1 (include) to 4 (exclude)
-myArray0.slice(1,4); // = [false,"js",12]
+// Get subarray of elements from index 1 (include) to 4 (exclude)
+myArray0.slice(1,4); // = [false,"js",12]
 
-// Remove 4 elements starting from index 2, and insert there strings
-// "hi","wr" and "ld"; return removed subarray
-myArray0.splice(2,4,"hi","wr","ld"); // = ["js",12,56,90]
-// myArray0 === [32,false,"hi","wr","ld"]
+// Remove 4 elements starting from index 2, and insert there strings
+// "hi","wr" and "ld"; return removed subarray
+myArray0.splice(2,4,"hi","wr","ld"); // = ["js",12,56,90]
+// myArray0 === [32,false,"hi","wr","ld"]
 
-// JavaScript's objects are equivalent to "dictionaries" or "maps" in other
-// languages: an unordered collection of key-value pairs.
-var myObj = {key1: "Hello", key2: "World"};
+// JavaScript's objects are equivalent to "dictionaries" or "maps" in other
+// languages: an unordered collection of key-value pairs.
+var myObj = {key1: "Hello", key2: "World"};
 
-// Keys are strings, but quotes aren't required if they're a valid
-// JavaScript identifier. Values can be any type.
-var myObj = {myKey: "myValue", "my other key": 4};
+// Keys are strings, but quotes aren't required if they're a valid
+// JavaScript identifier. Values can be any type.
+var myObj = {myKey: "myValue", "my other key": 4};
 
-// Object attributes can also be accessed using the subscript syntax,
-myObj["my other key"]; // = 4
+// Object attributes can also be accessed using the subscript syntax,
+myObj["my other key"]; // = 4
 
-// ... or using the dot syntax, provided the key is a valid identifier.
-myObj.myKey; // = "myValue"
+// ... or using the dot syntax, provided the key is a valid identifier.
+myObj.myKey; // = "myValue"
 
-// Objects are mutable; values can be changed and new keys added.
-myObj.myThirdKey = true;
+// Objects are mutable; values can be changed and new keys added.
+myObj.myThirdKey = true;
 
-// If you try to access a value that's not yet set, you'll get undefined.
-myObj.myFourthKey; // = undefined
+// If you try to access a value that's not yet set, you'll get undefined.
+myObj.myFourthKey; // = undefined
 
-///////////////////////////////////
-// 3. Logic and Control Structures
+///////////////////////////////////
+// 3. Logic and Control Structures
 
-// The `if` structure works as you'd expect.
-var count = 1;
-if (count == 3){
-    // evaluated if count is 3
-} else if (count == 4){
-    // evaluated if count is 4
-} else {
-    // evaluated if it's not either 3 or 4
+// The `if` structure works as you'd expect.
+var count = 1;
+if (count == 3){
+    // evaluated if count is 3
+} else if (count == 4){
+    // evaluated if count is 4
+} else {
+    // evaluated if it's not either 3 or 4
 }
 
-// As does `while`.
-while (true){
-    // An infinite loop!
+// As does `while`.
+while (true){
+    // An infinite loop!
 }
 
-// Do-while loops are like while loops, except they always run at least once.
-var input;
-do {
-    input = getInput();
-} while (!isValid(input));
+// Do-while loops are like while loops, except they always run at least once.
+var input;
+do {
+    input = getInput();
+} while (!isValid(input));
 
-// The `for` loop is the same as C and Java:
-// initialization; continue condition; iteration.
-for (var i = 0; i < 5; i++){
-    // will run 5 times
+// The `for` loop is the same as C and Java:
+// initialization; continue condition; iteration.
+for (var i = 0; i < 5; i++){
+    // will run 5 times
 }
 
-// Breaking out of labeled loops is similar to Java
+// Breaking out of labeled loops is similar to Java
 outer:
-for (var i = 0; i < 10; i++) {
-    for (var j = 0; j < 10; j++) {
-        if (i == 5 && j ==5) {
-            break outer;
-            // breaks out of outer loop instead of only the inner one
-        }
-    }
+for (var i = 0; i < 10; i++) {
+    for (var j = 0; j < 10; j++) {
+        if (i == 5 && j ==5) {
+            break outer;
+            // breaks out of outer loop instead of only the inner one
+        }
+    }
 }
 
-// The for/in statement allows iteration over properties of an object.
-var description = "";
-var person = {fname:"Paul", lname:"Ken", age:18};
-for (var x in person){
-    description += person[x] + " ";
-} // description = 'Paul Ken 18 '
-
-// The for/of statement allows iteration over iterable objects (including the built-in String, 
-// Array, e.g. the Array-like arguments or NodeList objects, TypedArray, Map and Set, 
-// and user-defined iterables).
-var myPets = "";
-var pets = ["cat", "dog", "hamster", "hedgehog"];
-for (var pet of pets){
-    myPets += pet + " ";
-} // myPets = 'cat dog hamster hedgehog '
-
-// && is logical and, || is logical or
-if (house.size == "big" && house.colour == "blue"){
-    house.contains = "bear";
+// The for/in statement allows iteration over properties of an object.
+var description = "";
+var person = {fname:"Paul", lname:"Ken", age:18};
+for (var x in person){
+    description += person[x] + " ";
+} // description = 'Paul Ken 18 '
+
+// The for/of statement allows iteration over iterable objects (including the built-in String, 
+// Array, e.g. the Array-like arguments or NodeList objects, TypedArray, Map and Set, 
+// and user-defined iterables).
+var myPets = "";
+var pets = ["cat", "dog", "hamster", "hedgehog"];
+for (var pet of pets){
+    myPets += pet + " ";
+} // myPets = 'cat dog hamster hedgehog '
+
+// && is logical and, || is logical or
+if (house.size == "big" && house.colour == "blue"){
+    house.contains = "bear";
 }
-if (colour == "red" || colour == "blue"){
-    // colour is either red or blue
+if (colour == "red" || colour == "blue"){
+    // colour is either red or blue
 }
 
-// && and || "short circuit", which is useful for setting default values.
-var name = otherName || "default";
-
-// The `switch` statement checks for equality with `===`.
-// Use 'break' after each case
-// or the cases after the correct one will be executed too.
-grade = 'B';
-switch (grade) {
-  case 'A':
-    console.log("Great job");
-    break;
-  case 'B':
-    console.log("OK job");
-    break;
-  case 'C':
-    console.log("You can do better");
-    break;
-  default:
-    console.log("Oy vey");
-    break;
+// && and || "short circuit", which is useful for setting default values.
+var name = otherName || "default";
+
+// The `switch` statement checks for equality with `===`.
+// Use 'break' after each case
+// or the cases after the correct one will be executed too.
+grade = 'B';
+switch (grade) {
+  case 'A':
+    console.log("Great job");
+    break;
+  case 'B':
+    console.log("OK job");
+    break;
+  case 'C':
+    console.log("You can do better");
+    break;
+  default:
+    console.log("Oy vey");
+    break;
 }
 
 
-///////////////////////////////////
-// 4. Functions, Scope and Closures
+///////////////////////////////////
+// 4. Functions, Scope and Closures
 
-// JavaScript functions are declared with the `function` keyword.
-function myFunction(thing){
-    return thing.toUpperCase();
+// JavaScript functions are declared with the `function` keyword.
+function myFunction(thing){
+    return thing.toUpperCase();
 }
-myFunction("foo"); // = "FOO"
-
-// Note that the value to be returned must start on the same line as the
-// `return` keyword, otherwise you'll always return `undefined` due to
-// automatic semicolon insertion. Watch out for this when using Allman style.
-function myFunction(){
-    return // <- semicolon automatically inserted here
-    {thisIsAn: 'object literal'};
+myFunction("foo"); // = "FOO"
+
+// Note that the value to be returned must start on the same line as the
+// `return` keyword, otherwise you'll always return `undefined` due to
+// automatic semicolon insertion. Watch out for this when using Allman style.
+function myFunction(){
+    return // <- semicolon automatically inserted here
+    {thisIsAn: 'object literal'};
 }
-myFunction(); // = undefined
+myFunction(); // = undefined
 
-// JavaScript functions are first class objects, so they can be reassigned to
-// different variable names and passed to other functions as arguments - for
-// example, when supplying an event handler:
-function myFunction(){
-    // this code will be called in 5 seconds' time
+// JavaScript functions are first class objects, so they can be reassigned to
+// different variable names and passed to other functions as arguments - for
+// example, when supplying an event handler:
+function myFunction(){
+    // this code will be called in 5 seconds' time
 }
-setTimeout(myFunction, 5000);
-// Note: setTimeout isn't part of the JS language, but is provided by browsers
-// and Node.js.
+setTimeout(myFunction, 5000);
+// Note: setTimeout isn't part of the JS language, but is provided by browsers
+// and Node.js.
 
-// Another function provided by browsers is setInterval
-function myFunction(){
-    // this code will be called every 5 seconds
+// Another function provided by browsers is setInterval
+function myFunction(){
+    // this code will be called every 5 seconds
 }
-setInterval(myFunction, 5000);
+setInterval(myFunction, 5000);
 
-// Function objects don't even have to be declared with a name - you can write
-// an anonymous function definition directly into the arguments of another.
+// Function objects don't even have to be declared with a name - you can write
+// an anonymous function definition directly into the arguments of another.
 setTimeout(function(){
-    // this code will be called in 5 seconds' time
-}, 5000);
+    // this code will be called in 5 seconds' time
+}, 5000);
 
-// JavaScript has function scope; functions get their own scope but other blocks
-// do not.
-if (true){
-    var i = 5;
+// JavaScript has function scope; functions get their own scope but other blocks
+// do not.
+if (true){
+    var i = 5;
 }
-i; // = 5 - not undefined as you'd expect in a block-scoped language
+i; // = 5 - not undefined as you'd expect in a block-scoped language
 
-// This has led to a common pattern of "immediately-executing anonymous
-// functions", which prevent temporary variables from leaking into the global
-// scope.
+// This has led to a common pattern of "immediately-executing anonymous
+// functions", which prevent temporary variables from leaking into the global
+// scope.
 (function(){
-    var temporary = 5;
-    // We can access the global scope by assigning to the "global object", which
-    // in a web browser is always `window`. The global object may have a
-    // different name in non-browser environments such as Node.js.
-    window.permanent = 10;
+    var temporary = 5;
+    // We can access the global scope by assigning to the "global object", which
+    // in a web browser is always `window`. The global object may have a
+    // different name in non-browser environments such as Node.js.
+    window.permanent = 10;
 })();
-temporary; // raises ReferenceError
-permanent; // = 10
-
-// One of JavaScript's most powerful features is closures. If a function is
-// defined inside another function, the inner function has access to all the
-// outer function's variables, even after the outer function exits.
-function sayHelloInFiveSeconds(name){
-    var prompt = "Hello, " + name + "!";
-    // Inner functions are put in the local scope by default, as if they were
-    // declared with `var`.
-    function inner(){
-        alert(prompt);
-    }
-    setTimeout(inner, 5000);
-    // setTimeout is asynchronous, so the sayHelloInFiveSeconds function will
-    // exit immediately, and setTimeout will call inner afterwards. However,
-    // because inner is "closed over" sayHelloInFiveSeconds, inner still has
-    // access to the `prompt` variable when it is finally called.
+temporary; // raises ReferenceError
+permanent; // = 10
+
+// One of JavaScript's most powerful features is closures. If a function is
+// defined inside another function, the inner function has access to all the
+// outer function's variables, even after the outer function exits.
+function sayHelloInFiveSeconds(name){
+    var prompt = "Hello, " + name + "!";
+    // Inner functions are put in the local scope by default, as if they were
+    // declared with `var`.
+    function inner(){
+        alert(prompt);
+    }
+    setTimeout(inner, 5000);
+    // setTimeout is asynchronous, so the sayHelloInFiveSeconds function will
+    // exit immediately, and setTimeout will call inner afterwards. However,
+    // because inner is "closed over" sayHelloInFiveSeconds, inner still has
+    // access to the `prompt` variable when it is finally called.
 }
-sayHelloInFiveSeconds("Adam"); // will open a popup with "Hello, Adam!" in 5s
+sayHelloInFiveSeconds("Adam"); // will open a popup with "Hello, Adam!" in 5s
 
-///////////////////////////////////
-// 5. More about Objects; Constructors and Prototypes
+///////////////////////////////////
+// 5. More about Objects; Constructors and Prototypes
 
-// Objects can contain functions.
-var myObj = {
-    myFunc: function(){
-        return "Hello world!";
-    }
+// Objects can contain functions.
+var myObj = {
+    myFunc: function(){
+        return "Hello world!";
+    }
 };
-myObj.myFunc(); // = "Hello world!"
-
-// When functions attached to an object are called, they can access the object
-// they're attached to using the `this` keyword.
-myObj = {
-    myString: "Hello world!",
-    myFunc: function(){
-        return this.myString;
-    }
+myObj.myFunc(); // = "Hello world!"
+
+// When functions attached to an object are called, they can access the object
+// they're attached to using the `this` keyword.
+myObj = {
+    myString: "Hello world!",
+    myFunc: function(){
+        return this.myString;
+    }
 };
-myObj.myFunc(); // = "Hello world!"
-
-// What this is set to has to do with how the function is called, not where
-// it's defined. So, our function doesn't work if it isn't called in the
-// context of the object.
-var myFunc = myObj.myFunc;
-myFunc(); // = undefined
-
-// Inversely, a function can be assigned to the object and gain access to it
-// through `this`, even if it wasn't attached when it was defined.
-var myOtherFunc = function(){
-    return this.myString.toUpperCase();
+myObj.myFunc(); // = "Hello world!"
+
+// What this is set to has to do with how the function is called, not where
+// it's defined. So, our function doesn't work if it isn't called in the
+// context of the object.
+var myFunc = myObj.myFunc;
+myFunc(); // = undefined
+
+// Inversely, a function can be assigned to the object and gain access to it
+// through `this`, even if it wasn't attached when it was defined.
+var myOtherFunc = function(){
+    return this.myString.toUpperCase();
 };
-myObj.myOtherFunc = myOtherFunc;
-myObj.myOtherFunc(); // = "HELLO WORLD!"
+myObj.myOtherFunc = myOtherFunc;
+myObj.myOtherFunc(); // = "HELLO WORLD!"
 
-// We can also specify a context for a function to execute in when we invoke it
-// using `call` or `apply`.
+// We can also specify a context for a function to execute in when we invoke it
+// using `call` or `apply`.
 
-var anotherFunc = function(s){
-    return this.myString + s;
+var anotherFunc = function(s){
+    return this.myString + s;
 };
-anotherFunc.call(myObj, " And Hello Moon!"); // = "Hello World! And Hello Moon!"
+anotherFunc.call(myObj, " And Hello Moon!"); // = "Hello World! And Hello Moon!"
 
-// The `apply` function is nearly identical, but takes an array for an argument
-// list.
+// The `apply` function is nearly identical, but takes an array for an argument
+// list.
 
-anotherFunc.apply(myObj, [" And Hello Sun!"]); // = "Hello World! And Hello Sun!"
+anotherFunc.apply(myObj, [" And Hello Sun!"]); // = "Hello World! And Hello Sun!"
 
-// This is useful when working with a function that accepts a sequence of
-// arguments and you want to pass an array.
+// This is useful when working with a function that accepts a sequence of
+// arguments and you want to pass an array.
 
-Math.min(42, 6, 27); // = 6
-Math.min([42, 6, 27]); // = NaN (uh-oh!)
-Math.min.apply(Math, [42, 6, 27]); // = 6
+Math.min(42, 6, 27); // = 6
+Math.min([42, 6, 27]); // = NaN (uh-oh!)
+Math.min.apply(Math, [42, 6, 27]); // = 6
 
-// But, `call` and `apply` are only temporary. When we want it to stick, we can
-// use `bind`.
+// But, `call` and `apply` are only temporary. When we want it to stick, we can
+// use `bind`.
 
-var boundFunc = anotherFunc.bind(myObj);
-boundFunc(" And Hello Saturn!"); // = "Hello World! And Hello Saturn!"
+var boundFunc = anotherFunc.bind(myObj);
+boundFunc(" And Hello Saturn!"); // = "Hello World! And Hello Saturn!"
 
-// `bind` can also be used to partially apply (curry) a function.
+// `bind` can also be used to partially apply (curry) a function.
 
-var product = function(a, b){ return a * b; };
-var doubler = product.bind(this, 2);
-doubler(8); // = 16
+var product = function(a, b){ return a * b; };
+var doubler = product.bind(this, 2);
+doubler(8); // = 16
 
-// When you call a function with the `new` keyword, a new object is created, and
-// made available to the function via the `this` keyword. Functions designed to be
-// called like that are called constructors.
+// When you call a function with the `new` keyword, a new object is created, and
+// made available to the function via the `this` keyword. Functions designed to be
+// called like that are called constructors.
 
-var MyConstructor = function(){
-    this.myNumber = 5;
+var MyConstructor = function(){
+    this.myNumber = 5;
 };
-myNewObj = new MyConstructor(); // = {myNumber: 5}
-myNewObj.myNumber; // = 5
-
-// Unlike most other popular object-oriented languages, JavaScript has no
-// concept of 'instances' created from 'class' blueprints; instead, JavaScript
-// combines instantiation and inheritance into a single concept: a 'prototype'.
-
-// Every JavaScript object has a 'prototype'. When you go to access a property
-// on an object that doesn't exist on the actual object, the interpreter will
-// look at its prototype.
-
-// Some JS implementations let you access an object's prototype on the magic
-// property `__proto__`. While this is useful for explaining prototypes it's not
-// part of the standard; we'll get to standard ways of using prototypes later.
-var myObj = {
-    myString: "Hello world!"
+myNewObj = new MyConstructor(); // = {myNumber: 5}
+myNewObj.myNumber; // = 5
+
+// Unlike most other popular object-oriented languages, JavaScript has no
+// concept of 'instances' created from 'class' blueprints; instead, JavaScript
+// combines instantiation and inheritance into a single concept: a 'prototype'.
+
+// Every JavaScript object has a 'prototype'. When you go to access a property
+// on an object that doesn't exist on the actual object, the interpreter will
+// look at its prototype.
+
+// Some JS implementations let you access an object's prototype on the magic
+// property `__proto__`. While this is useful for explaining prototypes it's not
+// part of the standard; we'll get to standard ways of using prototypes later.
+var myObj = {
+    myString: "Hello world!"
 };
-var myPrototype = {
-    meaningOfLife: 42,
-    myFunc: function(){
-        return this.myString.toLowerCase();
-    }
+var myPrototype = {
+    meaningOfLife: 42,
+    myFunc: function(){
+        return this.myString.toLowerCase();
+    }
 };
 
-myObj.__proto__ = myPrototype;
-myObj.meaningOfLife; // = 42
+myObj.__proto__ = myPrototype;
+myObj.meaningOfLife; // = 42
 
-// This works for functions, too.
-myObj.myFunc(); // = "hello world!"
+// This works for functions, too.
+myObj.myFunc(); // = "hello world!"
 
-// Of course, if your property isn't on your prototype, the prototype's
-// prototype is searched, and so on.
-myPrototype.__proto__ = {
-    myBoolean: true
+// Of course, if your property isn't on your prototype, the prototype's
+// prototype is searched, and so on.
+myPrototype.__proto__ = {
+    myBoolean: true
 };
-myObj.myBoolean; // = true
-
-// There's no copying involved here; each object stores a reference to its
-// prototype. This means we can alter the prototype and our changes will be
-// reflected everywhere.
-myPrototype.meaningOfLife = 43;
-myObj.meaningOfLife; // = 43
-
-// The for/in statement allows iteration over properties of an object,
-// walking up the prototype chain until it sees a null prototype.
-for (var x in myObj){
-    console.log(myObj[x]);
+myObj.myBoolean; // = true
+
+// There's no copying involved here; each object stores a reference to its
+// prototype. This means we can alter the prototype and our changes will be
+// reflected everywhere.
+myPrototype.meaningOfLife = 43;
+myObj.meaningOfLife; // = 43
+
+// The for/in statement allows iteration over properties of an object,
+// walking up the prototype chain until it sees a null prototype.
+for (var x in myObj){
+    console.log(myObj[x]);
 }
-///prints:
-// Hello world!
-// 43
-// [Function: myFunc]
-// true
-
-// To only consider properties attached to the object itself
-// and not its prototypes, use the `hasOwnProperty()` check.
-for (var x in myObj){
-    if (myObj.hasOwnProperty(x)){
-        console.log(myObj[x]);
-    }
+///prints:
+// Hello world!
+// 43
+// [Function: myFunc]
+// true
+
+// To only consider properties attached to the object itself
+// and not its prototypes, use the `hasOwnProperty()` check.
+for (var x in myObj){
+    if (myObj.hasOwnProperty(x)){
+        console.log(myObj[x]);
+    }
 }
-///prints:
-// Hello world!
-
-// We mentioned that `__proto__` was non-standard, and there's no standard way to
-// change the prototype of an existing object. However, there are two ways to
-// create a new object with a given prototype.
-
-// The first is Object.create, which is a recent addition to JS, and therefore
-// not available in all implementations yet.
-var myObj = Object.create(myPrototype);
-myObj.meaningOfLife; // = 43
-
-// The second way, which works anywhere, has to do with constructors.
-// Constructors have a property called prototype. This is *not* the prototype of
-// the constructor function itself; instead, it's the prototype that new objects
-// are given when they're created with that constructor and the new keyword.
-MyConstructor.prototype = {
-    myNumber: 5,
-    getMyNumber: function(){
-        return this.myNumber;
-    }
+///prints:
+// Hello world!
+
+// We mentioned that `__proto__` was non-standard, and there's no standard way to
+// change the prototype of an existing object. However, there are two ways to
+// create a new object with a given prototype.
+
+// The first is Object.create, which is a recent addition to JS, and therefore
+// not available in all implementations yet.
+var myObj = Object.create(myPrototype);
+myObj.meaningOfLife; // = 43
+
+// The second way, which works anywhere, has to do with constructors.
+// Constructors have a property called prototype. This is *not* the prototype of
+// the constructor function itself; instead, it's the prototype that new objects
+// are given when they're created with that constructor and the new keyword.
+MyConstructor.prototype = {
+    myNumber: 5,
+    getMyNumber: function(){
+        return this.myNumber;
+    }
 };
-var myNewObj2 = new MyConstructor();
-myNewObj2.getMyNumber(); // = 5
-myNewObj2.myNumber = 6;
-myNewObj2.getMyNumber(); // = 6
-
-// Built-in types like strings and numbers also have constructors that create
-// equivalent wrapper objects.
-var myNumber = 12;
-var myNumberObj = new Number(12);
-myNumber == myNumberObj; // = true
-
-// Except, they aren't exactly equivalent.
-typeof myNumber; // = 'number'
-typeof myNumberObj; // = 'object'
-myNumber === myNumberObj; // = false
-if (0){
-    // This code won't execute, because 0 is falsy.
+var myNewObj2 = new MyConstructor();
+myNewObj2.getMyNumber(); // = 5
+myNewObj2.myNumber = 6;
+myNewObj2.getMyNumber(); // = 6
+
+// Built-in types like strings and numbers also have constructors that create
+// equivalent wrapper objects.
+var myNumber = 12;
+var myNumberObj = new Number(12);
+myNumber == myNumberObj; // = true
+
+// Except, they aren't exactly equivalent.
+typeof myNumber; // = 'number'
+typeof myNumberObj; // = 'object'
+myNumber === myNumberObj; // = false
+if (0){
+    // This code won't execute, because 0 is falsy.
 }
-if (new Number(0)){
-   // This code will execute, because wrapped numbers are objects, and objects
-   // are always truthy.
+if (new Number(0)){
+   // This code will execute, because wrapped numbers are objects, and objects
+   // are always truthy.
 }
 
-// However, the wrapper objects and the regular builtins share a prototype, so
-// you can actually add functionality to a string, for instance.
-String.prototype.firstCharacter = function(){
-    return this.charAt(0);
+// However, the wrapper objects and the regular builtins share a prototype, so
+// you can actually add functionality to a string, for instance.
+String.prototype.firstCharacter = function(){
+    return this.charAt(0);
 };
-"abc".firstCharacter(); // = "a"
-
-// This fact is often used in "polyfilling", which is implementing newer
-// features of JavaScript in an older subset of JavaScript, so that they can be
-// used in older environments such as outdated browsers.
-
-// For instance, we mentioned that Object.create isn't yet available in all
-// implementations, but we can still use it with this polyfill:
-if (Object.create === undefined){ // don't overwrite it if it exists
-    Object.create = function(proto){
-        // make a temporary constructor with the right prototype
-        var Constructor = function(){};
-        Constructor.prototype = proto;
-        // then use it to create a new, appropriately-prototyped object
-        return new Constructor();
-    };
+"abc".firstCharacter(); // = "a"
+
+// This fact is often used in "polyfilling", which is implementing newer
+// features of JavaScript in an older subset of JavaScript, so that they can be
+// used in older environments such as outdated browsers.
+
+// For instance, we mentioned that Object.create isn't yet available in all
+// implementations, but we can still use it with this polyfill:
+if (Object.create === undefined){ // don't overwrite it if it exists
+    Object.create = function(proto){
+        // make a temporary constructor with the right prototype
+        var Constructor = function(){};
+        Constructor.prototype = proto;
+        // then use it to create a new, appropriately-prototyped object
+        return new Constructor();
+    };
 }
 
-// ES6 Additions
+// ES6 Additions
 
-// The "let" keyword allows you to define variables in a lexical scope, 
-// as opposed to a block scope like the var keyword does.
-let name = "Billy";
+// The "let" keyword allows you to define variables in a lexical scope, 
+// as opposed to a function scope like the var keyword does.
+let name = "Billy";
 
-// Variables defined with let can be reassigned new values.
-name = "William";
+// Variables defined with let can be reassigned new values.
+name = "William";
 
-// The "const" keyword allows you to define a variable in a lexical scope
-// like with let, but you cannot reassign the value once one has been assigned.
+// The "const" keyword allows you to define a variable in a lexical scope
+// like with let, but you cannot reassign the value once one has been assigned.
 
-const pi = 3.14;
+const pi = 3.14;
 
-pi = 4.13; // You cannot do this.
+pi = 4.13; // You cannot do this.
 
-// There is a new syntax for functions in ES6 known as "lambda syntax".
-// This allows functions to be defined in a lexical scope like with variables
-// defined by const and let. 
+// There is a new syntax for functions in ES6 known as "lambda syntax".
+// This allows functions to be defined in a lexical scope like with variables
+// defined by const and let. 
 
-const isEven = (number) => {
-    return number % 2 === 0;
+const isEven = (number) => {
+    return number % 2 === 0;
 };
 
-isEven(7); // false
+isEven(7); // false
 
-// The "equivalent" of this function in the traditional syntax would look like this:
+// The "equivalent" of this function in the traditional syntax would look like this:
 
-function isEven(number) {
-    return number % 2 === 0;
+function isEven(number) {
+    return number % 2 === 0;
 };
 
-// I put the word "equivalent" in double quotes because a function defined
-// using the lambda syntax cannnot be called before the definition.
-// The following is an example of invalid usage:
+// I put the word "equivalent" in double quotes because a function defined
+// using the lambda syntax cannot be called before the definition.
+// The following is an example of invalid usage:
 
-add(1, 8);
+add(1, 8);
 
-const add = (firstNumber, secondNumber) => {
-    return firstNumber + secondNumber;
+const add = (firstNumber, secondNumber) => {
+    return firstNumber + secondNumber;
 };
diff --git a/tests/results/23 b/tests/results/23
index e869a697..81441f54 100644
--- a/tests/results/23
+++ b/tests/results/23
@@ -22,5 +22,6 @@ print
 range
 rosetta/
 slices
+south meaning
 switch
 types
diff --git a/tests/results/25 b/tests/results/25
index bd555a8d..e69de29b 100644
--- a/tests/results/25
+++ b/tests/results/25
@@ -1,35 +0,0 @@
-# Latency numbers every programmer should know 
-
-1ns                          Main memory reference:       Send 2,000 bytes             Read 1,000,000 bytes         
-▗▖                           100ns                        over commodity network:      sequentially from SSD: 61us  
-                             ▗▖                           62ns                         ▗                            
-L1 cache reference: 1ns                                   ▗                                                         
-▗▖                           1us                                                       Disk seek: 2ms               
-                             ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         SSD random read: 16us        ▗▖▗▖▗                        
-Branch mispredict: 3ns                                    ▗▖                                                        
-▗▖▗▖▗▖                                                                                 Read 1,000,000 bytes         
-                             Compress 1KB with Snappy:     Read 1,000,000 bytes         sequentially from disk:      
-L2 cache reference: 4ns      2us                          sequentially from memory:    947us                        
-▗▖▗▖▗▖▗▖                     ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         3us                          ▗                            
-                             ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗                                                         
-Mutex lock/unlock: 16ns                                                                Packet roundtrip             
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      Round trip                   CA to Netherlands: 150ms     
-▗▖▗▖▗▖▗▖▗▖▗▖▗                10us = ▗▖                    in same datacenter: 500us    ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-                             ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-100ns = ▗▖                   ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         1ms = ▗▖                     ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-                                                          ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-                                                          ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖         
-# [github.com/chubin/late.nz] [MIT License]               ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      
-# Console port of "Jeff Dean's latency numbers"           ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      
-# from [github.com/colin-scott/interactive_latencies]     ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      
-                                                          ▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖▗▖                                      
diff --git a/tests/results/3 b/tests/results/3
index a271fdb6..eec4b43a 100644
--- a/tests/results/3
+++ b/tests/results/3
@@ -5,7 +5,7 @@ ls <dir>
 # To display everything in <dir>, including hidden files:
 ls -a <dir>
 
-# To display all files, along with the size (with unit suffixes) and timestamp
+# To display all files, along with the size (with unit suffixes) and timestamp:
 ls -lh <dir>
 
 # To display files, sorted by size:
@@ -16,6 +16,22 @@ ls -d */ <dir>
 
 # To display directories only, include hidden:
 ls -d .*/ */ <dir>
+
+# To display all files sorted by changed date, most recent first:
+ls -ltc 
+
+# To display files sorted by create time:
+ls -lt
+
+# To display files in a single column:
+ls -1
+
+# To show ACLs (MacOS):
+# see also `cheat chmod` for `/bin/chmod` options for ACLs
+/bin/ls -le
+
+# To show all the subtree files (Recursive Mode):
+ls -R
 #[tldr:ls]
 # ls
 # List directory contents.
diff --git a/tests/results/4 b/tests/results/4
index 692a2f66..ff839adf 100644
--- a/tests/results/4
+++ b/tests/results/4
@@ -1,76 +1,76 @@
  cheat.sheets:btrfs 
-# Create a btrfs file system on /dev/sdb, /dev/sdc, and /dev/sdd
-mkfs.btrfs /dev/sdb /dev/sdc /dev/sdd
+# Create a btrfs file system on /dev/sdb, /dev/sdc, and /dev/sdd
+mkfs.btrfs /dev/sdb /dev/sdc /dev/sdd
 
-# btrfs with just one hard drive, metadata not redundant
-# (this is dangerous: if your metadata is lost, your data is lost as well)
-mkfs.btrfs -m single /dev/sdb
+# btrfs with just one hard drive, metadata not redundant
+# (this is dangerous: if your metadata is lost, your data is lost as well)
+mkfs.btrfs -m single /dev/sdb
 
-# data to be redundant and metadata to be non-redundant:
-mkfs.btrfs -m raid0 -d raid1 /dev/sdb /dev/sdc /dev/sdd
+# data to be redundant and metadata to be non-redundant:
+mkfs.btrfs -m raid0 -d raid1 /dev/sdb /dev/sdc /dev/sdd
 
-# both data and metadata to be redundant
-mkfs.btrfs -d raid1 /dev/sdb /dev/sdc /dev/sdd
+# both data and metadata to be redundant
+mkfs.btrfs -d raid1 /dev/sdb /dev/sdc /dev/sdd
 
-# To get a list of all btrfs file systems
-btrfs filesystem show
+# To get a list of all btrfs file systems
+btrfs filesystem show
 
-# detailed df for a filesystem (mounted in /mnt)
-btrfs filesystem df /mnt
+# detailed df for a filesystem (mounted in /mnt)
+btrfs filesystem df /mnt
 
-# resize btrfs online (-2g decreases, +2g increases)
-btrfs filesystem resize -2g /mnt
+# resize btrfs online (-2g decreases, +2g increases)
+btrfs filesystem resize -2g /mnt
 
-# use maximum space
-btrfs filesystem resize max /mnt
+# use maximum space
+btrfs filesystem resize max /mnt
 
-# add new device to a filesystem
-btrfs device add /dev/sdf /mnt
+# add new device to a filesystem
+btrfs device add /dev/sdf /mnt
 
-# remove devices from a filesystem
-btrfs device delete missing /mnt
+# remove devices from a filesystem
+btrfs device delete missing /mnt
 
-# create the subvolume /mnt/sv1 in the /mnt volume
-btrfs subvolume create /mnt/sv1
+# create the subvolume /mnt/sv1 in the /mnt volume
+btrfs subvolume create /mnt/sv1
 
-# list subvolumes
-btrfs subvolume list /mnt
+# list subvolumes
+btrfs subvolume list /mnt
 
-# mount subvolume without mounting the main filesystem
-mount -o subvol=sv1 /dev/sdb /mnt
+# mount subvolume without mounting the main filesystem
+mount -o subvol=sv1 /dev/sdb /mnt
 
-# delete subvolume
-btrfs subvolume delete /mnt/sv1
+# delete subvolume
+btrfs subvolume delete /mnt/sv1
 
-# taking snapshot of a subvolume
-btrfs subvolume snapshot /mnt/sv1 /mnt/sv1_snapshot
+# taking snapshot of a subvolume
+btrfs subvolume snapshot /mnt/sv1 /mnt/sv1_snapshot
 
-# taking snapshot of a file (copy file by reference)
-cp --reflink /mnt/sv1/test1 /mnt/sv1/test3
+# taking snapshot of a file (copy file by reference)
+cp --reflink /mnt/sv1/test1 /mnt/sv1/test3
 
-# convert ext3/ext4 to btrfs
-btrfs-convert /dev/sdb1
+# convert ext3/ext4 to btrfs
+btrfs-convert /dev/sdb1
 
-# convert btrfs to ext3/ext4
-btrfs-convert -r /dev/sdb1
+# convert btrfs to ext3/ext4
+btrfs-convert -r /dev/sdb1
 
  tldr:btrfs 
-# btrfs
-# A filesystem based on the copy-on-write (COW) principle for Linux.
-# Some subcommands such as `btrfs device` have their own usage documentation.
-# More information: <https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs>.
+# btrfs
+# A filesystem based on the copy-on-write (COW) principle for Linux.
+# Some subcommands such as `btrfs device` have their own usage documentation.
+# More information: <https://btrfs.readthedocs.io/en/latest/btrfs.html>.
 
-# Create subvolume:
-sudo btrfs subvolume create path/to/subvolume
+# Create subvolume:
+sudo btrfs subvolume create path/to/subvolume
 
-# List subvolumes:
-sudo btrfs subvolume list path/to/mount_point
+# List subvolumes:
+sudo btrfs subvolume list path/to/mount_point
 
-# Show space usage information:
-sudo btrfs filesystem df path/to/mount_point
+# Show space usage information:
+sudo btrfs filesystem df path/to/mount_point
 
-# Enable quota:
-sudo btrfs quota enable path/to/subvolume
+# Enable quota:
+sudo btrfs quota enable path/to/subvolume
 
-# Show quota:
-sudo btrfs qgroup show path/to/subvolume
+# Show quota:
+sudo btrfs qgroup show path/to/subvolume
diff --git a/tests/results/5 b/tests/results/5
index d3accee7..d12963c9 100644
--- a/tests/results/5
+++ b/tests/results/5
@@ -1,55 +1,60 @@
  cheat.sheets:btrfs 
-# create the subvolume /mnt/sv1 in the /mnt volume
-btrfs subvolume create /mnt/sv1
+# create the subvolume /mnt/sv1 in the /mnt volume
+btrfs subvolume create /mnt/sv1
 
-# list subvolumes
-btrfs subvolume list /mnt
+# list subvolumes
+btrfs subvolume list /mnt
 
-# mount subvolume without mounting the main filesystem
-mount -o subvol=sv1 /dev/sdb /mnt
+# mount subvolume without mounting the main filesystem
+mount -o subvol=sv1 /dev/sdb /mnt
 
-# delete subvolume
-btrfs subvolume delete /mnt/sv1
+# delete subvolume
+btrfs subvolume delete /mnt/sv1
 
-# taking snapshot of a subvolume
-btrfs subvolume snapshot /mnt/sv1 /mnt/sv1_snapshot
+# taking snapshot of a subvolume
+btrfs subvolume snapshot /mnt/sv1 /mnt/sv1_snapshot
 
  tldr:btrfs 
-# Create subvolume:
-sudo btrfs subvolume create path/to/subvolume
+# Create subvolume:
+sudo btrfs subvolume create path/to/subvolume
 
-# List subvolumes:
-sudo btrfs subvolume list path/to/mount_point
+# List subvolumes:
+sudo btrfs subvolume list path/to/mount_point
 
-# Enable quota:
-sudo btrfs quota enable path/to/subvolume
+# Enable quota:
+sudo btrfs quota enable path/to/subvolume
 
-# Show quota:
-sudo btrfs qgroup show path/to/subvolume
+# Show quota:
+sudo btrfs qgroup show path/to/subvolume
 
  tldr:btrfs-filesystem 
-# Defragment a directory recursively (does not cross subvolume boundaries):
-sudo btrfs filesystem defragment -v -r path/to/directory
+# Defragment a directory recursively (does not cross subvolume boundaries):
+sudo btrfs filesystem defragment -v -r path/to/directory
+
+ tldr:btrfs-property 
+# btrfs property
+# Get, set, or list properties for a given btrfs filesystem object (files, directories, subvolumes, filesystems, or devices).
+# More information: <https://btrfs.readthedocs.io/en/latest/btrfs-property.html>.
 
  tldr:btrfs-subvolume 
-# btrfs subvolume
-# Manage btrfs subvolumes and snapshots.
-# More information: <https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume>.
+# btrfs subvolume
+# Manage btrfs subvolumes and snapshots.
+# More information: <https://btrfs.readthedocs.io/en/latest/btrfs-subvolume.html>.
 
-# Create a new empty subvolume:
-sudo btrfs subvolume create path/to/new_subvolume
+# Create a new empty subvolume:
+sudo btrfs subvolume create path/to/new_subvolume
 
-# List all subvolumes and snapshots in the specified filesystem:
-sudo btrfs subvolume list path/to/btrfs_filesystem
+# List all subvolumes and snapshots in the specified filesystem:
+sudo btrfs subvolume list path/to/btrfs_filesystem
 
-# Delete a subvolume:
-sudo btrfs subvolume delete path/to/subvolume
+# Delete a subvolume:
+sudo btrfs subvolume delete path/to/subvolume
 
-# Create a read-only snapshot of an existing subvolume:
-sudo btrfs subvolume snapshot -r path/to/source_subvolume path/to/target
+# Create a read-only snapshot of an existing subvolume:
+sudo btrfs subvolume snapshot -r path/to/source_subvolume path/to/target
 
-# Create a read-write snapshot of an existing subvolume:
-sudo btrfs subvolume snapshot path/to/source_subvolume path/to/target
+# Create a read-write snapshot of an existing subvolume:
+sudo btrfs subvolume snapshot path/to/source_subvolume path/to/target
 
-# Show detailed information about a subvolume:
-sudo btrfs subvolume show path/to/subvolume
+# Show detailed information about a subvolume:
+sudo btrfs subvolume show path/to/subvolume
diff --git a/tests/results/9 b/tests/results/9
index a8eca4f0..54d42a50 100644
--- a/tests/results/9
+++ b/tests/results/9
@@ -1,16 +1,23 @@
-#  How do I copy a file in Python?
+#  [`shutil`][1] has many methods you can use. One of which is:
 #  
-#  shutil (http://docs.python.org/3/library/shutil.html) has many methods
-#  you can use. One of which is:
-
-from shutil import copyfile
-
-copyfile(src, dst)
-
-#  Copy the contents of the file named src to a file named dst. The
-#  destination location must be writable; otherwise, an IOError exception
-#  will be raised. If dst already exists, it will be replaced. Special
-#  files such as character or block devices and pipes cannot be copied
-#  with this function. src and dst are path names given as strings.
+#  ```
+#  from shutil import copyfile
+#  copyfile(src, dst)
+#  ```
+#  
+ #  - Copy the contents of the file named **src** to a file named
+#  **dst**.
+ #  - The destination location must be writable; otherwise, an
+#  **IOError** exception will be raised.
+ #  - If **dst** already exists, it will be replaced.
+ #  - Special files such as character or block devices and pipes cannot
+#  be copied with this function.
+ #  - With **copy**, **src** and **dst** are path names given as
+#  __strings__.
+#  
+#  If you use `os.path` operations, use `copy` rather than `copyfile`.
+#  `copyfile` will only accept strings.
+#  
+  #  [1]: http://docs.python.org/3/library/shutil.html
 #  
 #  [Swati] [so/q/123198] [cc by-sa 3.0]

From 7dd29302924a15bb6deb141efd692c5f0586ec08 Mon Sep 17 00:00:00 2001
From: Bayram Tagiev <bayram.tagiev.a@gmail.com>
Date: Thu, 8 Jun 2023 12:06:30 +0300
Subject: [PATCH 2/2] tests: Added new trailing slash tests

---
 tests/results/26 | 310 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/results/27 | 310 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/tests.txt  |   2 +
 3 files changed, 622 insertions(+)
 create mode 100644 tests/results/26
 create mode 100644 tests/results/27

diff --git a/tests/results/26 b/tests/results/26
new file mode 100644
index 00000000..d14ec1f9
--- /dev/null
+++ b/tests/results/26
@@ -0,0 +1,310 @@
+// This is a comment. Line comments look like this...
+// and extend multiple lines like this.
+
+/// Documentation comments look like this and support markdown notation.
+/// # Examples
+///
+/// ```
+/// let five = 5
+/// ```
+
+///////////////
+// 1. Basics //
+///////////////
+
+#[allow(dead_code)]
+// Functions
+// `i32` is the type for 32-bit signed integers
+fn add2(x: i32, y: i32) -> i32 {
+    // Implicit return (no semicolon)
+    x + y
+}
+
+#[allow(unused_variables)]
+#[allow(unused_assignments)]
+#[allow(dead_code)]
+// Main function
+fn main() {
+    // Numbers //
+
+    // Immutable bindings
+    let x: i32 = 1;
+
+    // Integer/float suffixes
+    let y: i32 = 13i32;
+    let f: f64 = 1.3f64;
+
+    // Type inference
+    // Most of the time, the Rust compiler can infer what type a variable is, so
+    // you don’t have to write an explicit type annotation.
+    // Throughout this tutorial, types are explicitly annotated in many places,
+    // but only for demonstrative purposes. Type inference can handle this for
+    // you most of the time.
+    let implicit_x = 1;
+    let implicit_f = 1.3;
+
+    // Arithmetic
+    let sum = x + y + 13;
+
+    // Mutable variable
+    let mut mutable = 1;
+    mutable = 4;
+    mutable += 2;
+
+    // Strings //
+
+    // String literals
+    let x: &str = "hello world!";
+
+    // Printing
+    println!("{} {}", f, x); // 1.3 hello world
+
+    // A `String` – a heap-allocated string
+    // Stored as a `Vec<u8>` and always hold a valid UTF-8 sequence, 
+    // which is not null terminated.
+    let s: String = "hello world".to_string();
+
+    // A string slice – an immutable view into another string
+    // This is basically an immutable pair of pointers to a string – it doesn’t
+    // actually contain the contents of a string, just a pointer to
+    // the begin and a pointer to the end of a string buffer,
+    // statically allocated or contained in another object (in this case, `s`).
+    // The string slice is like a view `&[u8]` into `Vec<T>`.
+    let s_slice: &str = &s;
+
+    println!("{} {}", s, s_slice); // hello world hello world
+
+    // Vectors/arrays //
+
+    // A fixed-size array
+    let four_ints: [i32; 4] = [1, 2, 3, 4];
+
+    // A dynamic array (vector)
+    let mut vector: Vec<i32> = vec![1, 2, 3, 4];
+    vector.push(5);
+
+    // A slice – an immutable view into a vector or array
+    // This is much like a string slice, but for vectors
+    let slice: &[i32] = &vector;
+
+    // Use `{:?}` to print something debug-style
+    println!("{:?} {:?}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5]
+
+    // Tuples //
+
+    // A tuple is a fixed-size set of values of possibly different types
+    let x: (i32, &str, f64) = (1, "hello", 3.4);
+
+    // Destructuring `let`
+    let (a, b, c) = x;
+    println!("{} {} {}", a, b, c); // 1 hello 3.4
+
+    // Indexing
+    println!("{}", x.1); // hello
+
+    //////////////
+    // 2. Types //
+    //////////////
+
+    // Struct
+    struct Point {
+        x: i32,
+        y: i32,
+    }
+
+    let origin: Point = Point { x: 0, y: 0 };
+
+    // A struct with unnamed fields, called a ‘tuple struct’
+    struct Point2(i32, i32);
+
+    let origin2 = Point2(0, 0);
+
+    // Basic C-like enum
+    enum Direction {
+        Left,
+        Right,
+        Up,
+        Down,
+    }
+
+    let up = Direction::Up;
+
+    // Enum with fields
+    enum OptionalI32 {
+        AnI32(i32),
+        Nothing,
+    }
+
+    let two: OptionalI32 = OptionalI32::AnI32(2);
+    let nothing = OptionalI32::Nothing;
+
+    // Generics //
+
+    struct Foo<T> { bar: T }
+
+    // This is defined in the standard library as `Option`
+    enum Optional<T> {
+        SomeVal(T),
+        NoVal,
+    }
+
+    // Methods //
+
+    impl<T> Foo<T> {
+        // Methods take an explicit `self` parameter
+        fn bar(&self) -> &T { // self is borrowed
+            &self.bar
+        }
+        fn bar_mut(&mut self) -> &mut T { // self is mutably borrowed
+            &mut self.bar
+        }
+        fn into_bar(self) -> T { // here self is consumed
+            self.bar
+        }
+    }
+
+    let a_foo = Foo { bar: 1 };
+    println!("{}", a_foo.bar()); // 1
+
+    // Traits (known as interfaces or typeclasses in other languages) //
+
+    trait Frobnicate<T> {
+        fn frobnicate(self) -> Option<T>;
+    }
+
+    impl<T> Frobnicate<T> for Foo<T> {
+        fn frobnicate(self) -> Option<T> {
+            Some(self.bar)
+        }
+    }
+
+    let another_foo = Foo { bar: 1 };
+    println!("{:?}", another_foo.frobnicate()); // Some(1)
+
+    // Function pointer types // 
+
+    fn fibonacci(n: u32) -> u32 {
+        match n {
+            0 => 1,
+            1 => 1,
+            _ => fibonacci(n - 1) + fibonacci(n - 2),
+        }
+    }
+
+    type FunctionPointer = fn(u32) -> u32;
+
+    let fib : FunctionPointer = fibonacci;
+    println!("Fib: {}", fib(4)); // 5
+
+    /////////////////////////
+    // 3. Pattern matching //
+    /////////////////////////
+
+    let foo = OptionalI32::AnI32(1);
+    match foo {
+        OptionalI32::AnI32(n) => println!("it’s an i32: {}", n),
+        OptionalI32::Nothing  => println!("it’s nothing!"),
+    }
+
+    // Advanced pattern matching
+    struct FooBar { x: i32, y: OptionalI32 }
+    let bar = FooBar { x: 15, y: OptionalI32::AnI32(32) };
+
+    match bar {
+        FooBar { x: 0, y: OptionalI32::AnI32(0) } =>
+            println!("The numbers are zero!"),
+        FooBar { x: n, y: OptionalI32::AnI32(m) } if n == m =>
+            println!("The numbers are the same"),
+        FooBar { x: n, y: OptionalI32::AnI32(m) } =>
+            println!("Different numbers: {} {}", n, m),
+        FooBar { x: _, y: OptionalI32::Nothing } =>
+            println!("The second number is Nothing!"),
+    }
+
+    /////////////////////
+    // 4. Control flow //
+    /////////////////////
+
+    // `for` loops/iteration
+    let array = [1, 2, 3];
+    for i in array {
+        println!("{}", i);
+    }
+
+    // Ranges
+    for i in 0u32..10 {
+        print!("{} ", i);
+    }
+    println!("");
+    // prints `0 1 2 3 4 5 6 7 8 9 `
+
+    // `if`
+    if 1 == 1 {
+        println!("Maths is working!");
+    } else {
+        println!("Oh no...");
+    }
+
+    // `if` as expression
+    let value = if true {
+        "good"
+    } else {
+        "bad"
+    };
+
+    // `while` loop
+    while 1 == 1 {
+        println!("The universe is operating normally.");
+        // break statement gets out of the while loop.
+        //  It avoids useless iterations.
+        break
+    }
+
+    // Infinite loop
+    loop {
+        println!("Hello!");
+        // break statement gets out of the loop
+        break
+    }
+
+    /////////////////////////////////
+    // 5. Memory safety & pointers //
+    /////////////////////////////////
+
+    // Owned pointer – only one thing can ‘own’ this pointer at a time
+    // This means that when the `Box` leaves its scope, it can be automatically deallocated safely.
+    let mut mine: Box<i32> = Box::new(3);
+    *mine = 5; // dereference
+    // Here, `now_its_mine` takes ownership of `mine`. In other words, `mine` is moved.
+    let mut now_its_mine = mine;
+    *now_its_mine += 2;
+
+    println!("{}", now_its_mine); // 7
+    // println!("{}", mine); // this would not compile because `now_its_mine` now owns the pointer
+
+    // Reference – an immutable pointer that refers to other data
+    // When a reference is taken to a value, we say that the value has been ‘borrowed’.
+    // While a value is borrowed immutably, it cannot be mutated or moved.
+    // A borrow is active until the last use of the borrowing variable.
+    let mut var = 4;
+    var = 3;
+    let ref_var: &i32 = &var;
+
+    println!("{}", var); // Unlike `mine`, `var` can still be used
+    println!("{}", *ref_var);
+    // var = 5; // this would not compile because `var` is borrowed
+    // *ref_var = 6; // this would not either, because `ref_var` is an immutable reference
+    ref_var; // no-op, but counts as a use and keeps the borrow active
+    var = 2; // ref_var is no longer used after the line above, so the borrow has ended
+
+    // Mutable reference
+    // While a value is mutably borrowed, it cannot be accessed at all.
+    let mut var2 = 4;
+    let ref_var2: &mut i32 = &mut var2;
+    *ref_var2 += 2;         // '*' is used to point to the mutably borrowed var2
+
+    println!("{}", *ref_var2); // 6 , // var2 would not compile.
+    // ref_var2 is of type &mut i32, so stores a reference to an i32, not the value.
+    // var2 = 2; // this would not compile because `var2` is borrowed.
+    ref_var2; // no-op, but counts as a use and keeps the borrow active until here
+}
diff --git a/tests/results/27 b/tests/results/27
new file mode 100644
index 00000000..d14ec1f9
--- /dev/null
+++ b/tests/results/27
@@ -0,0 +1,310 @@
+// This is a comment. Line comments look like this...
+// and extend multiple lines like this.
+
+/// Documentation comments look like this and support markdown notation.
+/// # Examples
+///
+/// ```
+/// let five = 5
+/// ```
+
+///////////////
+// 1. Basics //
+///////////////
+
+#[allow(dead_code)]
+// Functions
+// `i32` is the type for 32-bit signed integers
+fn add2(x: i32, y: i32) -> i32 {
+    // Implicit return (no semicolon)
+    x + y
+}
+
+#[allow(unused_variables)]
+#[allow(unused_assignments)]
+#[allow(dead_code)]
+// Main function
+fn main() {
+    // Numbers //
+
+    // Immutable bindings
+    let x: i32 = 1;
+
+    // Integer/float suffixes
+    let y: i32 = 13i32;
+    let f: f64 = 1.3f64;
+
+    // Type inference
+    // Most of the time, the Rust compiler can infer what type a variable is, so
+    // you don’t have to write an explicit type annotation.
+    // Throughout this tutorial, types are explicitly annotated in many places,
+    // but only for demonstrative purposes. Type inference can handle this for
+    // you most of the time.
+    let implicit_x = 1;
+    let implicit_f = 1.3;
+
+    // Arithmetic
+    let sum = x + y + 13;
+
+    // Mutable variable
+    let mut mutable = 1;
+    mutable = 4;
+    mutable += 2;
+
+    // Strings //
+
+    // String literals
+    let x: &str = "hello world!";
+
+    // Printing
+    println!("{} {}", f, x); // 1.3 hello world
+
+    // A `String` – a heap-allocated string
+    // Stored as a `Vec<u8>` and always hold a valid UTF-8 sequence, 
+    // which is not null terminated.
+    let s: String = "hello world".to_string();
+
+    // A string slice – an immutable view into another string
+    // This is basically an immutable pair of pointers to a string – it doesn’t
+    // actually contain the contents of a string, just a pointer to
+    // the begin and a pointer to the end of a string buffer,
+    // statically allocated or contained in another object (in this case, `s`).
+    // The string slice is like a view `&[u8]` into `Vec<T>`.
+    let s_slice: &str = &s;
+
+    println!("{} {}", s, s_slice); // hello world hello world
+
+    // Vectors/arrays //
+
+    // A fixed-size array
+    let four_ints: [i32; 4] = [1, 2, 3, 4];
+
+    // A dynamic array (vector)
+    let mut vector: Vec<i32> = vec![1, 2, 3, 4];
+    vector.push(5);
+
+    // A slice – an immutable view into a vector or array
+    // This is much like a string slice, but for vectors
+    let slice: &[i32] = &vector;
+
+    // Use `{:?}` to print something debug-style
+    println!("{:?} {:?}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5]
+
+    // Tuples //
+
+    // A tuple is a fixed-size set of values of possibly different types
+    let x: (i32, &str, f64) = (1, "hello", 3.4);
+
+    // Destructuring `let`
+    let (a, b, c) = x;
+    println!("{} {} {}", a, b, c); // 1 hello 3.4
+
+    // Indexing
+    println!("{}", x.1); // hello
+
+    //////////////
+    // 2. Types //
+    //////////////
+
+    // Struct
+    struct Point {
+        x: i32,
+        y: i32,
+    }
+
+    let origin: Point = Point { x: 0, y: 0 };
+
+    // A struct with unnamed fields, called a ‘tuple struct’
+    struct Point2(i32, i32);
+
+    let origin2 = Point2(0, 0);
+
+    // Basic C-like enum
+    enum Direction {
+        Left,
+        Right,
+        Up,
+        Down,
+    }
+
+    let up = Direction::Up;
+
+    // Enum with fields
+    enum OptionalI32 {
+        AnI32(i32),
+        Nothing,
+    }
+
+    let two: OptionalI32 = OptionalI32::AnI32(2);
+    let nothing = OptionalI32::Nothing;
+
+    // Generics //
+
+    struct Foo<T> { bar: T }
+
+    // This is defined in the standard library as `Option`
+    enum Optional<T> {
+        SomeVal(T),
+        NoVal,
+    }
+
+    // Methods //
+
+    impl<T> Foo<T> {
+        // Methods take an explicit `self` parameter
+        fn bar(&self) -> &T { // self is borrowed
+            &self.bar
+        }
+        fn bar_mut(&mut self) -> &mut T { // self is mutably borrowed
+            &mut self.bar
+        }
+        fn into_bar(self) -> T { // here self is consumed
+            self.bar
+        }
+    }
+
+    let a_foo = Foo { bar: 1 };
+    println!("{}", a_foo.bar()); // 1
+
+    // Traits (known as interfaces or typeclasses in other languages) //
+
+    trait Frobnicate<T> {
+        fn frobnicate(self) -> Option<T>;
+    }
+
+    impl<T> Frobnicate<T> for Foo<T> {
+        fn frobnicate(self) -> Option<T> {
+            Some(self.bar)
+        }
+    }
+
+    let another_foo = Foo { bar: 1 };
+    println!("{:?}", another_foo.frobnicate()); // Some(1)
+
+    // Function pointer types // 
+
+    fn fibonacci(n: u32) -> u32 {
+        match n {
+            0 => 1,
+            1 => 1,
+            _ => fibonacci(n - 1) + fibonacci(n - 2),
+        }
+    }
+
+    type FunctionPointer = fn(u32) -> u32;
+
+    let fib : FunctionPointer = fibonacci;
+    println!("Fib: {}", fib(4)); // 5
+
+    /////////////////////////
+    // 3. Pattern matching //
+    /////////////////////////
+
+    let foo = OptionalI32::AnI32(1);
+    match foo {
+        OptionalI32::AnI32(n) => println!("it’s an i32: {}", n),
+        OptionalI32::Nothing  => println!("it’s nothing!"),
+    }
+
+    // Advanced pattern matching
+    struct FooBar { x: i32, y: OptionalI32 }
+    let bar = FooBar { x: 15, y: OptionalI32::AnI32(32) };
+
+    match bar {
+        FooBar { x: 0, y: OptionalI32::AnI32(0) } =>
+            println!("The numbers are zero!"),
+        FooBar { x: n, y: OptionalI32::AnI32(m) } if n == m =>
+            println!("The numbers are the same"),
+        FooBar { x: n, y: OptionalI32::AnI32(m) } =>
+            println!("Different numbers: {} {}", n, m),
+        FooBar { x: _, y: OptionalI32::Nothing } =>
+            println!("The second number is Nothing!"),
+    }
+
+    /////////////////////
+    // 4. Control flow //
+    /////////////////////
+
+    // `for` loops/iteration
+    let array = [1, 2, 3];
+    for i in array {
+        println!("{}", i);
+    }
+
+    // Ranges
+    for i in 0u32..10 {
+        print!("{} ", i);
+    }
+    println!("");
+    // prints `0 1 2 3 4 5 6 7 8 9 `
+
+    // `if`
+    if 1 == 1 {
+        println!("Maths is working!");
+    } else {
+        println!("Oh no...");
+    }
+
+    // `if` as expression
+    let value = if true {
+        "good"
+    } else {
+        "bad"
+    };
+
+    // `while` loop
+    while 1 == 1 {
+        println!("The universe is operating normally.");
+        // break statement gets out of the while loop.
+        //  It avoids useless iterations.
+        break
+    }
+
+    // Infinite loop
+    loop {
+        println!("Hello!");
+        // break statement gets out of the loop
+        break
+    }
+
+    /////////////////////////////////
+    // 5. Memory safety & pointers //
+    /////////////////////////////////
+
+    // Owned pointer – only one thing can ‘own’ this pointer at a time
+    // This means that when the `Box` leaves its scope, it can be automatically deallocated safely.
+    let mut mine: Box<i32> = Box::new(3);
+    *mine = 5; // dereference
+    // Here, `now_its_mine` takes ownership of `mine`. In other words, `mine` is moved.
+    let mut now_its_mine = mine;
+    *now_its_mine += 2;
+
+    println!("{}", now_its_mine); // 7
+    // println!("{}", mine); // this would not compile because `now_its_mine` now owns the pointer
+
+    // Reference – an immutable pointer that refers to other data
+    // When a reference is taken to a value, we say that the value has been ‘borrowed’.
+    // While a value is borrowed immutably, it cannot be mutated or moved.
+    // A borrow is active until the last use of the borrowing variable.
+    let mut var = 4;
+    var = 3;
+    let ref_var: &i32 = &var;
+
+    println!("{}", var); // Unlike `mine`, `var` can still be used
+    println!("{}", *ref_var);
+    // var = 5; // this would not compile because `var` is borrowed
+    // *ref_var = 6; // this would not either, because `ref_var` is an immutable reference
+    ref_var; // no-op, but counts as a use and keeps the borrow active
+    var = 2; // ref_var is no longer used after the line above, so the borrow has ended
+
+    // Mutable reference
+    // While a value is mutably borrowed, it cannot be accessed at all.
+    let mut var2 = 4;
+    let ref_var2: &mut i32 = &mut var2;
+    *ref_var2 += 2;         // '*' is used to point to the mutably borrowed var2
+
+    println!("{}", *ref_var2); // 6 , // var2 would not compile.
+    // ref_var2 is of type &mut i32, so stores a reference to an i32, not the value.
+    // var2 = 2; // this would not compile because `var2` is borrowed.
+    ref_var2; // no-op, but counts as a use and keeps the borrow active until here
+}
diff --git a/tests/tests.txt b/tests/tests.txt
index 86bcc529..b7a2dd89 100644
--- a/tests/tests.txt
+++ b/tests/tests.txt
@@ -23,3 +23,5 @@ javascript/:learn           # short names check
 emacs:go-mode/:list         # special editor names
 mkffs.ffatt                 # unknown
 latencies                   # [python2]
+rust/:learn
+rust/:learn/