code: def _new_redis_client(self):
          
          if 'tornadoredis' not in globals():
              import tornadoredis
          kwargs = self._redis_connection_settings()
          LOGGER.info('Connecting to %(host)s:%(port)s DB %(selected_db)s',
                      kwargs)
          return tornadoredis.Client(**kwargs)
docs: Create a new redis client and assign it the class _redis_client
          attribute for reuse across requests.
  
          :rtype: tornadoredis.Client()