'Get the latest data and updates the state.'

def update(self):

    _LOGGER.debug('Pulling    data    from    %s    sensor', self._name)
    self._data.update()
    if (self._sensor_type == 'volume'):
        self._state = self._data.volume
    if (self._sensor_type == 'battery'):
        self._state = self._data.battery_life
    if self._sensor_type.startswith('last_'):
        history = self._data.history(timezone=self._tz, kind=self._kind)
        if history:
            self._extra = history[0]
            created_at = self._extra['created_at']
            self._state = '{0:0>2}:{1:0>2}'.format(created_at.hour, created_at.minute)
