/**
  * @param $courier
  * @return mixed
  * @throws ProductNotFoundException
  */
 public function finalize($courier)
 {
     if ($this->tracking()) {
         $order = new Order();
         $order->setProduct($this->getTracked());
         // create order in database
         $order->make();
         $biller = $this->getBiller($courier);
         return $order->bill($biller);
     } else {
         throw new ProductNotFoundException();
     }
 }