/**
  * @param $entity
  * @param $group
  * @return mixed
  */
 public function extractEntity($entity, $group)
 {
     $serializedContext = SerializationContext::create()->setGroups(array($group))->setSerializeNull(true);
     return $this->transformer->transformExtractData(json_decode($this->serializer->serialize($entity, 'json', $serializedContext), true));
 }
 /**
  * @param $data
  * @param $entityName
  * @return mixed
  */
 public function hydrateEntity($data, $entityName)
 {
     return $this->serializer->deserialize($this->transformer->transformHydrateData($data), $entityName, 'json');
 }