code: func (v *Dialog) GetContentArea() (*Box, error) {
  	c := C.gtk_dialog_get_content_area(v.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	obj := glib.Take(unsafe.Pointer(c))
  	b := &Box{Container{Widget{glib.InitiallyUnowned{obj}}}}
  	return b, nil
  }
docs: // GetContentArea() is a wrapper around gtk_dialog_get_content_area().