public function __construct(Model $model, Model $parentModel, $relation, $relationRaw = null)
 {
     parent::__construct($model);
     $this->parentModel = $parentModel;
     $this->relation = $relation;
     $this->relationRaw = $relationRaw ?: "{$relation}Raw";
 }
 /**
  * @param int|object|Model $object
  * @param object|Model $parent
  * @param array $input
  * @return object|Model
  */
 public function updateForParent($object, $parent, $input)
 {
     $parent = $this->getParentModel($parent);
     if ($object instanceof Model == false) {
         $object = $this->getForParent($object, $parent);
     }
     return parent::update($object, $input);
 }