public function settings_init() {

    add_action( 'load-' . $this->pagehook, [ $this, 'metaboxes' ] );
    add_action( $this->pagehook . '_settings_page_boxes', [ $this, 'do_metaboxes' ] );

    if ( method_exists( $this, 'layout_columns' ) ) {
      add_filter( 'screen_layout_columns', [ $this, 'layout_columns' ], 10, 2 );
    }

  }