protected function writeSmokeCredentials($url = null)
    {
        if (defined('SMOKE_CREDENTIALS')) {
            $this->output->writeln("\n " . SMOKE_CREDENTIALS . "\n");
        } else {
            $this->output->writeln("\n Smoke " . SMOKE_VERSION . " by Nils Langner\n");
        }

        if ($url) {
            $this->output->writeln(' <info>Scanning ' . $url . "</info>\n");
        }
    }