public function load(ObjectManager $dm)
 {
     if (!$dm instanceof DocumentManager) {
         $class = get_class($dm);
         throw new \RuntimeException("Fixture requires a PHPCR ODM DocumentManager instance, instance of '{$class}' given.");
     }
     $parent = $dm->find(null, '/cms/articles');
     $rootArticle = new Article();
     $rootArticle->setTitle('main');
     $rootArticle->setParentDocument($parent);
     $dm->persist($rootArticle);
     $articel = new Article();
     $articel->setTitle('Home article');
     $articel->setParentDocument($rootArticle);
     $articel->setContent("Welcome to the homepage of this really basic CMS.");
     $dm->persist($articel);
     $aboutArticle = new Article();
     $aboutArticle->setTitle('About articles');
     $aboutArticle->setParentDocument($rootArticle);
     $aboutArticle->setContent("Some lorem about ipsum.");
     $dm->persist($aboutArticle);
     $dm->flush();
 }