private function registerPage($title, $capabilities, $url_param, $class, $callback, $type)
    {
        if ($type == 'submenu') {
            add_submenu_page($this->url, $title, $title, $capabilities, $url_param, array(
                $class,
                $callback
            ));
        } else {
            add_menu_page($title, $title, $capabilities, $url_param, array(
                $class,
                $callback
            ));
        }
    }