final protected function generateUrl($domain_key, $path = '/')
    {
        $base_domain = self::$URL_MAP[$domain_key];
        $base_domain = str_replace('{domain}', $this->domain, $base_domain);

        if ($path[0] === '/') {
            $path = substr($path, 1);
        }

        return $base_domain.$path;
    }