'Retrieves the dead letter source queues for a given queue.
:type queue: A :class:`boto.sqs.queue.Queue` object.
:param queue: The queue for which to get DL source queues
:rtype: list
:returns: A list of :py:class:`boto.sqs.queue.Queue` instances.'

def get_dead_letter_source_queues(self, queue):

    params = {'QueueUrl': queue.url}
    return self.get_list('ListDeadLetterSourceQueues', params, [('QueueUrl', Queue)])
