/**
  * Prepares the given entity data for comparison with $entity.
  * That is, this method should add any extra data from $entity to $entityData.
  *
  * @param Entity $entity
  * @param array $entityData
  */
 protected function prepareEntityData(Entity $entity, array &$entityData)
 {
     /* @var Property $entity */
     $entityData['datatype'] = $entity->getDataTypeId();
 }