def METHOD_NAME(self):
    # serial's built-in check doesn't work too well on win32 so just try
    # all
    if sys.platform == 'win32':
        return ['COM' + str(i) for i in range(20)]
    # on linux and mac the options are too wide so use serial.tools
    from serial.tools import list_ports
    poss = list_ports.comports()
    # filter out any that report 'n/a' for their hardware
    final = []
    for p in poss:
        if p[2] != 'n/a':
            final.append(p[0])  # just the port address
    return final