code: func RadioButtonNewWithLabel(group *glib.SList, label string) (*RadioButton, error) {
  	cstr := C.CString(label)
  	defer C.free(unsafe.Pointer(cstr))
  	c := C.gtk_radio_button_new_with_label(cGSList(group), (*C.gchar)(cstr))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapRadioButton(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // RadioButtonNewWithLabel is a wrapper around
  // gtk_radio_button_new_with_label().