code: def _connection(self, value):
          
          if isinstance(value, _Pipeline):
              self._pipelined_connection = value
          else:
              self._direct_connection = value
              self._pipelined_connection = None
docs: If the value is a pipeline, save it as the connection to use for pipelines if to be shared
          in threads or goot thread. Do not remove the direct connection.
          If it is not a pipeline, clear it, and set the direct connection again.