code: protected function loadArnk(Segment\ArrivalUnknown $segment)
      {
          $this->travelProduct = new TravelProduct();
          $this->travelProduct->productDetails = new ProductDetails($segment->identification);
          $this->messageAction = new MessageAction(Business::FUNC_ARNK);
      }
docs: Load Arrival Unknown element
  
  @param Segment\ArrivalUnknown $segment