protected function pageTypeOptions()
    {
        $pageTypes = [];
        $classes = ArrayLib::valueKey(SiteTree::page_type_classes());
        unset($classes['VirtualPage']);
        unset($classes['ErrorPage']);
        unset($classes['RedirectorPage']);
        foreach ($classes as $pageTypeClass) {
            $pageTypes[$pageTypeClass] = singleton($pageTypeClass)->i18n_singular_name();
        }
        asort($pageTypes);

        return $pageTypes;
    }