human
I wrote the below code

    name = config.get(CONF_NAME)
    host = config.get(CONF_HOST)
    port = config.get(CONF_PORT)
    username = config.get(CONF_USERNAME)
    password = config.get(CONF_PASSWORD)
    phonebook_id = config.get('phonebook')
    prefixes = config.get('prefixes')
    try:
        phonebook = FritzBoxPhonebook(host=host, port=port, username=username, password=password, phonebook_id=phonebook_id, prefixes=prefixes)
    except:
        phonebook = None
        _LOGGER.warning('Phonebook    with    ID    %s    not    found    on    Fritz!Box', phonebook_id)
    sensor = FritzBoxCallSensor(name=name, phonebook=phonebook)
    add_devices([sensor])
    monitor = FritzBoxCallMonitor(host=host, port=port, sensor=sensor)
    monitor.connect()
    def _stop_listener(_event):
        monitor.stopped.set()
    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, _stop_listener)
    return (monitor.sock is not None)

What's a good function header?
assistant
#Here's a good function header.

def setup_platform(hass, config, add_devices, discovery_info=None):