Dojo Toolkit "inherited" with JS strict mode

startup.js

require([
  "dojo/_base/declare",
  "dijit/_WidgetBase"
], function (declare){
  "use strict";
  return declare("WidgetClass", _WidgetBase, {
    startup: function startup(){
      this.inherited({
        callee: startup
      }, arguments);
    }
  });
});