public function renderSitemap(array $entries)
    {
        $data = '<?xml version="1.0" encoding="UTF-8"?>' . PHP_EOL;
        $data .= '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . PHP_EOL;
        foreach ($entries as $entry) {
            $data .= '    <url>' . PHP_EOL;
            $data .= '        <loc>' . $entry->getLoc() . '</loc>' . PHP_EOL;
            if (null !== $entry->getLastMod()) {
                $data .= '        <lastmod>' . $entry->getLastMod() . '</lastmod>' . PHP_EOL;
            }
            if (null !== $entry->getChangeFreq()) {
                $data .= '        <changefreq>' . $entry->getChangeFreq() . '</changefreq>' . PHP_EOL;
            }
            if (null !== $entry->getPriority()) {
                $data .= '        <priority>' . $entry->getPriority() . '</priority>' . PHP_EOL;
            }
            $data .= '    </url>' . PHP_EOL;
        }

        $data .= '</urlset>' . PHP_EOL;

        return $data;
    }