public static function is_cartridge($url) {
        $params = self::validate_parameters(self::is_cartridge_parameters(),
                                            array(
                                                'url' => $url,
                                            ));
        $url = $params['url'];

        $context = context_system::instance();
        self::validate_context($context);
        require_capability('moodle/site:config', $context);

        $iscartridge = lti_is_cartridge($url);

        return array('iscartridge' => $iscartridge);
    }