public function fetch($what = null, $live = false) {
        // not supported?
        if(!in_array($what, ['style', 'script']))
            throw new Exception("{$what} not supported");

        // compress?
        $this->compress = !Configure::read('debug') || $live == true;

        // call private function
        $function = '_' . $what;
        echo $this->$function();
    }