$r = [
            'form_action' => isset($extra['form_action']) ? $extra['form_action'] : url('/@object/@action/@id/@page'),
            'add_link' => isset($extra['add_link']) ? $extra['add_link'] : url('/@object/add_item/@id/@page'),
            'back_link' => isset($extra['back_link']) ? $extra['back_link'] : url('/@object/show_items/@id/@page'),
        ];