code: function () {
  
              Overlay.superclass.initEvents.call(this);
  
              var SIGNATURE = CustomEvent.LIST;
  
              /**
              * CustomEvent fired before the Overlay is moved.
              * @event beforeMoveEvent
              * @param {Number} x x coordinate
              * @param {Number} y y coordinate
              */
              this.beforeMoveEvent = this.createEvent(EVENT_TYPES.BEFORE_MOVE);
              this.beforeMoveEvent.signature = SIGNATURE;
  
              /**
              * CustomEvent fired after the Overlay is moved.
              * @event moveEvent
              * @param {Number} x x coordinate
              * @param {Number} y y coordinate
              */
              this.moveEvent = this.createEvent(EVENT_TYPES.MOVE);
              this.moveEvent.signature = SIGNATURE;
  
          }
docs: Initializes the custom events for Overlay which are fired
  automatically at appropriate times by the Overlay class.
  @method initEvents