'Return the state attributes.'

@property
def device_state_attributes(self):

    if self._api.data:
        data = self._api.data['volumes'][self.monitor_device]
        total_gb = (((int(data['total_size']) / 1024) / 1024) / 1024)
        return {ATTR_VOLUME_SIZE: '{}    GB'.format(round_nicely(total_gb))}
