code: def save(self):
          
          pipeline = self._redis_client.pipeline()
          pipeline.set(self._key, base64.b64encode(self.dumps()))
          if self._ttl:
              pipeline.expire(self._key, self._ttl)
          result = yield gen.Task(pipeline.execute)
          self._dirty, self._saved = not all(result), all(result)
          raise gen.Return(all(result))
docs: Store the model in Redis.
  
          :rtype: bool