$sitemap = new Sitemap();
$sitemap->add(
new SitemapItem('http://example.com', new DateTime(), ChangeFrequency::ALWAYS(), 90)
);
echo $sitemap->toString()$sitemap = new Sitemap();
$sitemap->add(new GoogleNewsItem(
new SitemapItem('http://example.com'),
'Example', 'en', 'Subject', new DateTime()
));
echo $sitemap->toString();