public Container addChild(@NonNull DisplayObject DisplayObject){
  if (mFps != DEFAULT_FPS) {
    DisplayObject.setUp(mFps);
  }
  mDisplayList.add(DisplayObject);
  return this;
}

public Container addChild ( @ NonNull DisplayObject DisplayObject ) { if ( mFps != DEFAULT_FPS ) { DisplayObject . setUp ( mFps ) ; } mDisplayList . add ( DisplayObject ) ; return this ; }
adds a child to the top of the display list .
