code: def _restore_queue(self):
          
          if self.queue is not None:
              # Clear the queue so that it can be reset
              self.device.clear_queue()
              # Now loop around all the queue entries adding them
              for queue_group in self.queue:
                  for queue_item in queue_group:
                      self.device.add_uri_to_queue(queue_item.uri)
docs: Restore the previous state of the queue.
  
          Note:
              The restore currently adds the items back into the queue
              using the URI, for items the Sonos system already knows about
              this is OK, but for other items, they may be missing some of
              their metadata as it will not be automatically picked up.