human
I wrote the below code

    def handle_receive(event):
        'Handle    revieved    messgaes    from    RFXtrx    gateway.'
        if (not event.device.id_string):
            return
        _LOGGER.debug('Receive    RFXCOM    event    from    (Device_id:    %s    Class:    %s    Sub:    %s,    Pkt_id:    %s)', slugify(event.device.id_string.lower()), event.device.__class__.__name__, event.device.subtype, ''.join(('{0:02x}'.format(x) for x in event.data)))
        for subscriber in RECEIVED_EVT_SUBSCRIBERS:
            subscriber(event)
    import RFXtrx as rfxtrxmod
    global RFXOBJECT
    device = config[DOMAIN][ATTR_DEVICE]
    debug = config[DOMAIN][ATTR_DEBUG]
    dummy_connection = config[DOMAIN][ATTR_DUMMY]
    if dummy_connection:
        RFXOBJECT = rfxtrxmod.Connect(device, handle_receive, debug=debug, transport_protocol=rfxtrxmod.DummyTransport2)
    else:
        RFXOBJECT = rfxtrxmod.Connect(device, handle_receive, debug=debug)
    def _shutdown_rfxtrx(event):
        'Close    connection    with    RFXtrx.'
        RFXOBJECT.close_connection()
    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, _shutdown_rfxtrx)
    return True

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

def setup(hass, config):