/**
  * Because the Item structure is of Array type we
  * need to pass in the parent ID differently
  * For now we can just hard code an :id field but later
  * it needs to have keys for various reasons
  * 
  * @see JSONSchema\Structure.Property::loadFields()
  */
 public function loadFields($parentId = null)
 {
     $arrParentId = $parentId ? $parentId . '/:id' : null;
     return parent::loadFields($arrParentId);
 }