code: protected function getSaleFromItem(Model\SaleItemInterface $item)
      {
          if (null !== $sale = $item->getSale()) {
              return $sale;
          }
  
          $path = $this->getSalePropertyPath();
          $cs = $this->persistenceHelper->getChangeSet($item);
  
          if (isset($cs[$path])) {
              return $cs[$path][0];
          } elseif (null !== $parent = $item->getParent()) {
              return $this->getSaleFromItem($parent);
          } elseif (isset($cs['parent'])) {
              return $this->getSaleFromItem($cs['parent'][0]);
          }
  
          return null;
      }
docs: Returns the sale from the given sale item (looking into change set).
  
  @param Model\SaleItemInterface $item
  
  @return Model\SaleInterface|null