'Retrieve latest state.'

@asyncio.coroutine
def async_update(self):

    _LOGGER.debug('Updating    Room    sensor:    %s', self._sensor)
    temp = self._eight.room_temperature()
    if (self._units == 'si'):
        self._state = round(temp, 2)
    else:
        self._state = round(((temp * 1.8) + 32), 2)
