code: def restore(self):
          
          if not self._snapshot:
              return
          yield from self.set_muted(self._snapshot['muted'])
          yield from self.set_volume(self._snapshot['volume'])
          yield from self.set_stream(self._snapshot['stream'])
          self.callback()
          _LOGGER.info('restored snapshot of state of %s', self.friendly_name)
docs: Restore snapshotted state.