News sitemap gives an error in Google if no posts are chosen

If there aren’t any posts flagged for the news sitemap when Google scans it then it returns this error for the sitemap_index.xml:

Missing XML tag. This required tag is missing. Please add it and resubmit.

Which is annoying, but not breaking anything. To work around this I added this code to the constructor in xml-news-sitemap-class.xml to skip including the news-sitemap.xml in the sitemap_index.xml when there’s no content in it.

/**
  * Class constructor
  */
public function __construct() {
  global $wpdb;

  // Always create the sitemap (even when empty) so we don't have 404 messages for it...
  add_action( 'init', array( $this, 'init' ), 10 );
  add_action( 'wpseo_head', array( $this, 'head' ) );

  // ...but only add the news sitemap to the index when we have available items for it
  $items = $wpdb->get_results( "SELECT ID FROM $wpdb->posts JOIN $wpdb->postmeta ON ID = post_id
        WHERE post_status='publish'
          AND (DATEDIFF(CURDATE(), post_date_gmt)<=2)
          AND meta_key = '_yoast_wpseo_newssitemap-include'
          AND meta_value = 'on'
          LIMIT 0, 10" );

  if ( !empty( $items ) ) {
     add_filter( 'wpseo_sitemap_index', array( $this, 'add_to_index' ) );
  }
}

https://www.ads-software.com/extend/plugins/wordpress-seo-news/