public static function import($json_str)
    {
        try {
            $json = json_decode($json_str); 
            // print_r($json);
            $retval = new MenuSet();
            $retval->home = new \Tsugi\UI\MenuEntry($json->home->link, $json->home->href);
            if ( isset($json->left) ) $retval->left = self::importRecurse($json->left, 0);
            if ( isset($json->right) ) $retval->right = self::importRecurse($json->right, 0);
            return $retval;
        } catch (Exception $e) {
            return false;
        }
    }