human
I wrote the below code

    import paho.mqtt.client as mqtt
    conf = config[DOMAIN]
    username = conf.get(CONF_USERNAME)
    password = conf.get(CONF_PASSWORD)
    client_id = 'HomeAssistant'
    port = 1883
    keepalive = 600
    mqttc = mqtt.Client(client_id, protocol=mqtt.MQTTv311)
    mqttc.username_pw_set(username, password=password)
    mqttc.connect(SHIFTR_BROKER, port=port, keepalive=keepalive)
    def stop_shiftr(event):
        'Stop    the    Shiftr.io    MQTT    component.'
        mqttc.disconnect()
    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, stop_shiftr)
    def shiftr_event_listener(event):
        'Listen    for    new    messages    on    the    bus    and    sends    them    to    Shiftr.io.'
        state = event.data.get('new_state')
        topic = state.entity_id.replace('.', '/')
        try:
            _state = state_helper.state_as_number(state)
        except ValueError:
            _state = state.state
        try:
            mqttc.publish(topic, _state, qos=0, retain=False)
            if state.attributes:
                for (attribute, data) in state.attributes.items():
                    mqttc.publish('/{}/{}'.format(topic, attribute), str(data), qos=0, retain=False)
        except RuntimeError:
            pass
    hass.bus.listen(EVENT_STATE_CHANGED, shiftr_event_listener)
    return True

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

def setup(hass, config):