code: def _get_key_value(self, key, is_hll=False):
          '''
          Returns the proper key value for the stats
          @param key: the redis key
          @param is_hll: the key is a HyperLogLog, else is a sorted set
          '''
          if is_hll:
              return self.redis_conn.execute_command("PFCOUNT", key)
          else:
              return self.redis_conn.zcard(key)