'Return the state attributes.'

@property
def device_state_attributes(self):

    attributes = {}
    battery = self._battery_level
    if battery:
        attributes[ATTR_BATTERY_LEVEL] = battery
    man_dev_model = self._manufacturer_device_model
    if man_dev_model:
        attributes['manufacturer_device_model'] = man_dev_model
    man_dev_id = self._manufacturer_device_id
    if man_dev_id:
        attributes['manufacturer_device_id'] = man_dev_id
    dev_man = self._device_manufacturer
    if dev_man:
        attributes['device_manufacturer'] = dev_man
    model_name = self._model_name
    if model_name:
        attributes['model_name'] = model_name
    tamper = self._tamper
    if (tamper is not None):
        attributes['tamper_detected'] = tamper
    return attributes
