code: func (v *Container) GetFocusChild() *Widget {
  	c := C.gtk_container_get_focus_child(v.native())
  	if c == nil {
  		return nil
  	}
  	obj := glib.Take(unsafe.Pointer(c))
  	return wrapWidget(obj)
  }
docs: // TODO: gtk_container_get_path_for_child
  // GetFocusChild is a wrapper around gtk_container_get_focus_child().