Removes the tasks from the queue.

    Note that tasks can already have been removed. It is not an error
    to re-delete an already deleted task.

    Args:
     queue: A queue to clear.
     tasks: A list of tasks to remove. Tasks may be Task() instances or integers
       representing the task_id.
     mutation_pool: A MutationPool object to schedule deletions on.

    Raises:
      ValueError: Mutation pool was not passed in.

def Delete(self, queue, tasks, mutation_pool=None):
    """Removes the tasks from the queue.

    Note that tasks can already have been removed. It is not an error
    to re-delete an already deleted task.

    Args:
     queue: A queue to clear.
     tasks: A list of tasks to remove. Tasks may be Task() instances or integers
       representing the task_id.
     mutation_pool: A MutationPool object to schedule deletions on.

    Raises:
      ValueError: Mutation pool was not passed in.
    """
    if queue is None:
      return
    if mutation_pool is None:
      raise ValueError("Mutation pool can't be none.")
    mutation_pool.QueueDeleteTasks(queue, tasks)