public function maybe_add_submenu() { // Maybe add submenu. if ( isset( $this->menu_ops['submenu'] ) && is_array( $this->menu_ops['submenu'] ) ) { $menu = wp_parse_args( $this->menu_ops['submenu'], [ 'parent_slug' => '', 'page_title' => '', 'menu_title' => '', 'capability' => 'edit_theme_options', ] ); $this->pagehook = add_submenu_page( $menu['parent_slug'], $menu['page_title'], $menu['menu_title'], $menu['capability'], $this->page_id, [ $this, 'admin' ] ); } }