code: function (type, args, obj) {
              var visible = args[0];
              if (visible) {
                  this.beforeShowEvent.fire();
                  Dom.setStyle(this.element, "display", "block");
                  this.showEvent.fire();
              } else {
                  this.beforeHideEvent.fire();
                  Dom.setStyle(this.element, "display", "none");
                  this.hideEvent.fire();
              }
          }
docs: BUILT-IN EVENT HANDLERS FOR MODULE // 
  Default event handler for changing the visibility property of a
  Module. By default, this is achieved by switching the "display" style
  between "block" and "none".
  This method is responsible for firing showEvent and hideEvent.
  @param {String} type The CustomEvent type (usually the property name)
  @param {Object[]} args The CustomEvent arguments. For configuration
  handlers, args[0] will equal the newly applied value for the property.
  @param {Object} obj The scope object. For configuration handlers,
  this will usually equal the owner.
  @method configVisible