code: def _reset_docs(self):
          
          _LOGGER.debug("resetting documents")
          self.change_map.clear()
          self.resume_token = None
  
          # Mark each document as deleted. If documents are not deleted
          # they will be sent again by the server.
          for snapshot in self.doc_tree.keys():
              name = snapshot.reference._document_path
              self.change_map[name] = ChangeType.REMOVED
  
          self.current = False
docs: Helper to clear the docs on RESET or filter mismatch.