serial.serialutil.PortNotOpenError: Attempting to use a port that is not open

[gokul6350]

OS: Ubuntu 22.04.3 LTS x86_64
recently installed pyserial
worked fine with windows but not work in linux
even arduino serial working well
I know that only 1 application can use a serial at a time
i arduino IDE it shows it is connected at /dev/ttyACM0
even i gave all the permission

Exception has occurred: PortNotOpenError
Attempting to use a port that is not open
File "/home/gokul/Desktop/Yolo-ARM/Code/useless/check.py", line 14, in base_turn
connection.write(data.encode())
File "/home/gokul/Desktop/Yolo-ARM/Code/useless/check.py", line 39, in
base_turn(90)
serial.serialutil.PortNotOpenError: Attempting to use a port that is not open

code :

import serial

# Replace '/dev/ttyUSB0' with the appropriate serial port on your Linux system
port = '/dev/ttyACM0'


try:
    connection = serial.Serial(port, 9600)
    print(f"Serial {port} is working well")

    def base_turn(ang):
        rounded_ang = round(ang)
        data = f"b{rounded_ang}"
        connection.write(data.encode())

    def shoulder(ang):
        rounded_ang = round(ang) + 60
        data = f"s{rounded_ang}"
        connection.write(data.encode())

    def elbow(ang):
        rounded_ang = round(ang) + 34
        data = f"e{rounded_ang}"
        connection.write(data.encode())

    def gripper(ang):
        rounded_ang = round(ang)
        data = f"h{rounded_ang}"
        connection.write(data.encode())

except serial.SerialException as e:
    print(f"Failed to open serial port {port}: {e}")

# Add error handling and close the serial connection when done
finally:
    if 'connection' in locals() and connection.is_open:
        connection.close()
        
base_turn(90)