code: def NotifyAboutEnd(self):
      
      flow_ref = None
      if self.runner_args.client_id:
        flow_ref = rdf_objects.FlowReference(
            client_id=self.client_id, flow_id=self.urn.Basename())
  
      num_results = len(self.ResultCollection())
      notification_lib.Notify(
          self.creator, rdf_objects.UserNotification.Type.TYPE_FLOW_RUN_COMPLETED,
          "Flow %s completed with %d %s" %
          (self.__class__.__name__, num_results, num_results == 1 and "result" or
           "results"),
          rdf_objects.ObjectReference(
              reference_type=rdf_objects.ObjectReference.Type.FLOW,
              flow=flow_ref))
docs: Send out a final notification about the end of this flow.