Sample program to find the serial port

auto_select_port_name.py

import sys
from serial.tools import list_ports

def auto_select_port_name(port_name):
    if port_name:
        return port_name
    port_names = [port.device for port in list_ports.comports()]
    port_names.sort()
    if len(port_names) == 0:
        return None
    elif len(port_names) == 1:
        return port_names[0]
    print("Available ports:")
    for i in range(len(port_names)):
        print(" %d --> %s" % (i,port_names[i]))
    print("enter number >> ", end="")
    num = int(input())
    return port_names[num]

port_name = auto_select_port_name(sys.argv[1] if len(sys.argv) >= 2 else None)
print(port_name)