docs: function () {
                  var eventListeners = this._cfg ? this._cfg.on : null;
                  if (eventListeners) {
                      for (var listener in eventListeners) {
                          if (eventListeners.hasOwnProperty(listener)) {
                              eventListeners[listener] = this.$normCallback(eventListeners[listener]);
                          }
                      }
                  }
              }