code: def _add_kickoff_task(cls,
                          base_path,
                          mapreduce_spec,
                          eta,
                          countdown,
                          queue_name):
      
      params = {"mapreduce_id": mapreduce_spec.mapreduce_id}
      # Task is not named so that it can be added within a transaction.
      kickoff_task = taskqueue.Task(
          url=base_path + "/kickoffjob_callback/" + mapreduce_spec.mapreduce_id,
          headers=util._get_task_headers(mapreduce_spec.mapreduce_id),
          params=params,
          eta=eta,
          countdown=countdown)
      hooks = mapreduce_spec.get_hooks()
      if hooks is not None:
        try:
          hooks.enqueue_kickoff_task(kickoff_task, queue_name)
          return
        except NotImplementedError:
          pass
      kickoff_task.add(queue_name, transactional=True)
docs: Enqueues a new kickoff task.