Bare-bones Python COM PORT tester

import serial
import serial.tools.list_ports

def get_port():
    ports = serial.tools.list_ports.comports()
    if 0 == len(ports):
        print("No COM ports found!")
        return None
    else:
        print("Detected COM ports:")
        for i, port in enumerate(ports):
            print(i, ": ", port)
        index = int(input("Select number of desired port: "))
    port = ports[index].device
    return serial.Serial(port, 115200)

my_port = get_port()
if None != my_port:
    print("Connected, start sending bytes...")
    while True:
        c = my_port.read()
        if 0 < len(c):
            value = (c[0] + 1) & 0xFF
            my_port.write(bytes([value]))