code: func RadioButtonNewFromWidget(radioGroupMember *RadioButton) (*RadioButton, error) {
  	c := C.gtk_radio_button_new_from_widget(radioGroupMember.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapRadioButton(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // RadioButtonNewFromWidget is a wrapper around
  // gtk_radio_button_new_from_widget().