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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 names(self):
 """ Returns a list of queues available, ``None`` if no such queues found. Remember this will only shows queues with at least one item enqueued. """

        data = None
        if not self.connected:
            raise ConnectionError('Queue is not connected')

        try:
            data = self.rdb.keys("retaskqueue-*")
        except redis.exceptions.ConnectionError as err:
            raise ConnectionError(str(err))

        return [name[12:] for name in data]