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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:
 async def ack(self, tube, task_id):
 """ Report task successful execution. Ack is accepted only from the consumer, which took the task for execution. If a consumer disconnects, all tasks taken by this consumer are put back to READY state (released). Returns tarantool tuple object. """

        cmd = tube.cmd("ack")
        args = (task_id,)

        res = await self.tnt.call(cmd, args)
        return res