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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def schedule(cls, mapreduce_spec):
 """Schedule finalize task. Args: mapreduce_spec: mapreduce specification as MapreduceSpec. """

    task_name = mapreduce_spec.mapreduce_id + "-finalize"
    finalize_task = taskqueue.Task(
        name=task_name,
        url=(mapreduce_spec.params["base_path"] + "/finalizejob_callback/" +
             mapreduce_spec.mapreduce_id),
        params={"mapreduce_id": mapreduce_spec.mapreduce_id},
        headers=util._get_task_headers(mapreduce_spec.mapreduce_id))
    queue_name = util.get_queue_name(None)
    if not _run_task_hook(mapreduce_spec.get_hooks(),
                          "enqueue_controller_task",
                          finalize_task,
                          queue_name):
      try:
        finalize_task.add(queue_name)
      except (taskqueue.TombstonedTaskError,
              taskqueue.TaskAlreadyExistsError), e:
        logging.warning("Task %r already exists. %s: %s",
                        task_name, e.__class__, e)