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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 accumulate(a_generator, cooperator=None):
 """ Start a Deferred whose callBack arg is a deque of the accumulation of the values yielded from a_generator. :param a_generator: An iterator which yields some not None values. :return: A Deferred to which the next callback will be called with the yielded contents of the generator function. """

    if cooperator:
        own_cooperate = cooperator.cooperate
    else:
        own_cooperate = cooperate

    spigot = ValueBucket()
    items = stream_tap((spigot,), a_generator)
    d = own_cooperate(items).whenDone()
    d.addCallback(accumulation_handler, spigot)
    return d