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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 send(self, task, result, expire=60):
 """ Sends the result back to the producer. This should be called if only you want to return the result in async manner. :arg task: ::class:`~retask.task.Task` object :arg result: Result data to be send back. Should be in JSON serializable. :arg expire: Time in seconds after the key expires. Default is 60 seconds. """

        self.rdb.lpush(task.urn, json.dumps(result))
        self.rdb.expire(task.urn, expire)