function suppress_php_warnings() {
    error_reporting(E_ALL & ~E_WARNING);
    @ini_set('display_errors', 0);
    @ini_set('log_errors', 0);
}
add_action('after_setup_theme', 'suppress_php_warnings');
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://lastpintprod.com/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://lastpintprod.com/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://lastpintprod.com/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://lastpintprod.com/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://lastpintprod.com/wp-sitemap-taxonomies-post_tag-1.xml</loc></sitemap><sitemap><loc>https://lastpintprod.com/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>