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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 queueStream(self, rdds, oneAtATime=True, default=None):
 """Create stream iterable over RDDs. :param rdds: Iterable over RDDs or lists. :param oneAtATime: Process one at a time or all. :param default: If no more RDDs in ``rdds``, return this. Can be None. :rtype: DStream Example: [4] [2] [7] Example testing the default value: [4] [2] ['placeholder'] """

        deserializer = QueueStreamDeserializer(self._context)
        if default is not None:
            default = deserializer(default)

        if Queue is False:
            log.error('Run "pip install tornado" to install tornado.')

        q = Queue()
        for i in rdds:
            q.put(i)

        qstream = QueueStream(q, oneAtATime, default)
        return DStream(qstream, self, deserializer)