code: func (w *Window) AddLabel(x, y int, format string, args ...interface{}) *Label {
  	// we can ignore error for builtins
  	l, _ := w.AddWidget(WidgetLabel, x, y)
  	label := l.(*Label)
  	label.Resize()
  	label.SetAttributes(defaultAttributes())
  	label.SetText(format, args...)
  
  	return label
  }
docs: // AddLabel is a convenience function to add a new label to a window.  It wraps
  // the AddWidget call.  AddLabel must be called from queue.