protected function loadGlobal(/*# string */ $group)
    {
        if (!isset($GLOBALS[$group])) {
            $this->throwError(
                Message::get(Message::CONFIG_GLOBAL_UNKNOWN, $group),
                Message::CONFIG_GLOBAL_UNKNOWN
            );
        }

        // load super global
        $this->config->addNode($group, $GLOBALS[$group]);

        return $this;
    }