public function load(ObjectManager $manager)
 {
     $data = $this->container->get('ilioscore.dataloader.courseLearningMaterial')->getAll();
     foreach ($data as $arr) {
         $entity = new CourseLearningMaterial();
         $entity->setId($arr['id']);
         $entity->setRequired($arr['required']);
         $entity->setPublicNotes($arr['publicNotes']);
         $entity->setNotes($arr['notes']);
         $entity->setCourse($this->getReference('courses' . $arr['course']));
         $entity->setLearningMaterial($this->getReference('learningMaterials' . $arr['learningMaterial']));
         $manager->persist($entity);
         $this->addReference('courseLearningMaterials' . $arr['id'], $entity);
     }
     $manager->flush();
 }