protected function convertNodes(Array $nodes, $em) {
    // our test project (this) is defined to have only de as i18n but dont get confused, these are english wordings
    $navigationNodes = array();

    foreach ($nodes as $node) {
      $node = (object) $node;
      $navigationNode = $this->createNode(array('de'=>$node->title));
      $navigationNode->setContext($this->context);
      $navigationNode->generateSlugs();

      $page = $this->createPage($navigationNode->getSlug('de'));
      $page->setActive(TRUE);
      $em->persist($page);

      $navigationNode->setPage($page);

      $navigationNodes[$navigationNode->getTitle('de')] = $navigationNode;
    }

    foreach ($nodes as $node) {
      $node = (object) $node;

      if (isset($node->parent)) {
        $navigationNodes[$node->title]->setParent($navigationNodes[$node->parent]);
      }
    }

    return $navigationNodes;
  }