code: func (v *ToolItem) RetrieveProxyMenuItem() *MenuItem {
  	c := C.gtk_tool_item_retrieve_proxy_menu_item(v.native())
  	if c == nil {
  		return nil
  	}
  	return wrapMenuItem(glib.Take(unsafe.Pointer(c)))
  }
docs: // RetrieveProxyMenuItem is a wrapper around
  // gtk_tool_item_retrieve_proxy_menu_item()