/**
  * @param PageInterface $page
  * @param PageInterface $currentPage
  * @param array         $choices
  * @param int           $level
  */
 private function childWalker(PageInterface $page, PageInterface $currentPage = null, &$choices, $level = 1)
 {
     if (!($currentPage && $currentPage->getId() == $page->getId())) {
         $choices[$page->getId()] = $page->getLongName();
         foreach ($page->getChildren() as $child) {
             $this->childWalker($child, $currentPage, $choices, $level + 1);
         }
     }
 }