Create a new redis client and assign it the class _redis_client
        attribute for reuse across requests.

        :rtype: tornadoredis.Client()

def _new_redis_client(self):
        """Create a new redis client and assign it the class _redis_client
        attribute for reuse across requests.

        :rtype: tornadoredis.Client()

        """
        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)