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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 exists(self):
 """ Returns true if the job is still running or zero-os still knows about this job ID After a job is finished, a job remains on zero-os for max of 5min where you still can read the job result after the 5 min is gone, the job result is no more fetchable :return: bool """

        r = self._client._redis
        flag = '{}:flag'.format(self._queue)
        return bool(r.exists(flag))