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