code: public function getOrFail()
      {
          $model = $this->get();
  
          if (is_null($model)) {
              throw new ParentModelNotFoundException($this->parentClass, $this->child->getParentId());
          }
  
          return $model;
      }
docs: Return parent model.
  
  @throws ParentModelNotFoundException
  @return ElasticsearchModel