serial.tools.list_ports.comports() does not work_ubuntu_20.04

[Konstantinos Malakis]

I use python3.8.8 in ubuntu 20.04.2 LTS and i want a list with my all usb ports. So when i write in terminal "python3 -m serial.tools.list_ports" -> no ports found. I saw the bug #1470314 and i tried to change the lines as you said, but i didn't work. I changed the file <list_ports_posix.py> at "/home/konstantinos/.local/lib/python3.8/site-packages/serial/tools" .

apt-cache policy python3-serial:
"python3-serial:
  Installed: (none)
  Candidate: 3.4-5.1
  Version table:
     3.4-5.1 500
        500 http://gr.archive.ubuntu.com/ubuntu focal/main amd64 Packages
        500 http://gr.archive.ubuntu.com/ubuntu focal/main i386 Packages
"

Thank you