code: function loadScript(redis, script_name, script, callback) {
    redis.multi()
      .script('load', script)
      .exec(function (err, sha1) {
        if (err) {
          return callback(err);
        }
        shas[script_name] = sha1 && sha1.length && sha1[0];
        callback(null, sha1);
      });
  }
docs: Load a script into the script cache