protected function sandbox(&$locate, UrlGenerator $url, array $options = [])
    {
        $sandbox = (isset($options['sandbox']) && $options['sandbox'] == false) ? null : $url->getRequest()->query('sandbox');
        if (!is_null($sandbox)) {
            $separator = (parse_url($locate, PHP_URL_QUERY) == NULL) ? '?' : '&';
            $locate    .= $separator . 'sandbox=' . $sandbox;
        }
        return $locate;
    }