Metro_Sitemap::get_supported_post_types_in PHP Method

    private static function get_supported_post_types_in()
    {
        global $wpdb;
        $post_types_in = '';
        $post_types = self::get_supported_post_types();
        $post_types_prepared = array();
        foreach ($post_types as $post_type) {
            $post_types_prepared[] = $wpdb->prepare('%s', $post_type);
        }
        return implode(', ', $post_types_prepared);
    }