/**
  * Change a purchasble on the holder
  * @param \Heystack\Ecommerce\Purchasable\Interfaces\PurchasableInterface $purchasable
  * @param int $quantity
  * @return void
  */
 protected function changePurchasableQuantity(PurchasableInterface $purchasable, $quantity)
 {
     if ($purchasable->getQuantity() !== $quantity) {
         $purchasable->setQuantity($quantity);
         $this->updateTotal();
         $this->eventService->dispatch(Events::PURCHASABLE_CHANGED);
     }
 }
 /**
  * @param \SS_HTTPRequest $request
  * @param \Heystack\Ecommerce\Purchasable\Interfaces\PurchasableInterface $purchasable
  * @return array
  */
 protected function removePurchasable(\SS_HTTPRequest $request, PurchasableInterface $purchasable)
 {
     $this->purchasableHolder->removePurchasable($purchasable->getIdentifier());
     return $this->succeeded($purchasable);
 }