code: func RadioMenuItemNewFromWidget(group *RadioMenuItem) (*RadioMenuItem, error) {
  	c := C.gtk_radio_menu_item_new_from_widget(group.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapRadioMenuItem(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // RadioMenuItemNewFromWidget is a wrapper around
  // gtk_radio_menu_item_new_from_widget().