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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 save(self):
 """Store the session data in redis :param method callback: The callback method to invoke when done """

        result = yield gen.Task(RedisSession._redis_client.set,
                                self._key, self.dumps())
        LOGGER.debug('Saved session %s (%r)', self.id, result)
        raise gen.Return(result)