public static function pre_get_posts( $query ) {

    // Bail if not home or not main query.
    if ( ! $query->is_home() || ! $query->is_main_query() ) {
      return;
    }

    // Bail if the blog page is not the front page.
    if ( 'posts' !== get_option( 'show_on_front' ) ) {
      return;
    }

    $featured = self::get_featured_post_ids();

    // Bail if no featured posts.
    if ( ! $featured ) {
      return;
    }

    // We need to respect post ids already in the blacklist.
    $post__not_in = $query->get( 'post__not_in' );

    if ( ! empty( $post__not_in ) ) {
      $featured = array_merge( (array) $post__not_in, $featured );
      $featured = array_unique( $featured );
    }

    $query->set( 'post__not_in', $featured );
  }