[fix] accept null for properties

Author: Marcel Hauri

app/code/Magento/InstantPurchase/Model/InstantPurchaseOption.php

@@ -20,22 +20,22 @@
 class InstantPurchaseOption
 {
     /**
-     * @var PaymentTokenInterface
+     * @var PaymentTokenInterface|null
      */
     private $paymentToken;
 
     /**
-     * @var Address
+     * @var Address|null
      */
     private $shippingAddress;
 
     /**
-     * @var Address
+     * @var Address|null
      */
     private $billingAddress;
 
     /**
-     * @var ShippingMethodInterface
+     * @var ShippingMethodInterface|null
      */
     private $shippingMethod;