human
Here's a good function header given the following:
I wrote the below code

    from decora_wifi import DecoraWiFiSession
    from decora_wifi.models.person import Person
    from decora_wifi.models.residential_account import ResidentialAccount
    email = config.get(CONF_USERNAME)
    password = config.get(CONF_PASSWORD)
    session = DecoraWiFiSession()
    try:
        success = session.login(email, password)
        if (success is None):
            msg = 'Failed    to    log    into    myLeviton    Services.    Check    credentials.'
            _LOGGER.error(msg)
            hass.components.persistent_notification.create(msg, title=NOTIFICATION_TITLE, notification_id=NOTIFICATION_ID)
            return False
        perms = session.user.get_residential_permissions()
        all_switches = []
        for permission in perms:
            acct = ResidentialAccount(session, permission.residentialAccountId)
            for residence in acct.get_residences():
                for switch in residence.get_iot_switches():
                    all_switches.append(switch)
        add_devices((DecoraWifiLight(sw) for sw in all_switches))
    except ValueError:
        _LOGGER.error('Failed    to    communicate    with    myLeviton    Service.')
    def logout(event):
        'Log    out...'
        try:
            if (session is not None):
                Person.logout(session)
        except ValueError:
            _LOGGER.error('Failed    to    log    out    of    myLeviton    Service.')
    hass.bus.listen(EVENT_HOMEASSISTANT_STOP, logout)

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

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