code: private function saveResult(AbstractDiffItem $item, $action)
      {
          $this->storage->save(
              $action,
              $item->getCategory(),
              $item->getItemId(),
              $item->getTimestamp(),
              $this->getShopIds()
          );
      }
docs: Save results to storage.
  
  @param AbstractDiffItem $item
  @param string           $action