🐛 Bug

Hi, I'm following the example shown in the README, but I am getting the following error when I attempt to import programl:

>>> import programl as pg
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/m/code/tinkervenv/lib/python3.11/site-packages/programl/__init__.py", line 55, in <module>
    from programl.transform_ops import to_dgl, to_dot, to_json, to_networkx
  File "/home/m/code/tinker/venv/lib/python3.11/site-packages/programl/transform_ops.py", line 25, in <module>
    from dgl.heterograph import DGLHeteroGraph
ImportError: cannot import name 'DGLHeteroGraph' from 'dgl.heterograph' (/home/m/code/tinker/venv/lib/python3.11/site-packages/dgl/heterograph.py)

To Reproduce

Steps to reproduce the behavior:

1. Create a virtual environment.
2. Run the following command to install programl:

pip install -U programl

3. Open a Python shell and attempt to import programl package:

>>> import programl

Expected behavior

The package should be imported without any errors.

Environment

• ProGraML version: 0.3.2
• How you installed ProGraML: pip
• OS: Linux 6.1.37-lts, EndeavourOS
• Python version: 3.11.3
• Versions of any other relevant libraries: dgl-1.1.1

Additional context

Using pip freeze | grep dgl to inspect the installed version is dgl==1.1.1 which has breaking changing in the DGLHeteroGraph API. I have also tried to manually downgrading dgl and got the following error:

$ pip install dgl==0.6.1
ERROR: Could not find a version that satisfies the requirement dgl==0.6.1 (from versions: 0.1.0, 0.1.2, 0.1.3, 1.0.0, 1.0.1, 1.0.4, 1.1.0, 1.1.1)
ERROR: No matching distribution found for dgl==0.6.1

which confirms that dgl-0.6.1 doesn't include a distributed package for Python 3.11