anchor.diff:                  if (lineItemRemoved.ID != null) {
                       OnDeleteLineItem(lineItemRemoved.ID);
                   }
  -                
  +
                   return true;
               }
           }
  
positive.code:                 bool didUpdateID = false;
                  string checkoutVariantId = checkoutLineItem.variant().id();
                  string checkoutLineItemId = checkoutLineItem.id();
                  
                  foreach(CartLineItem cartLineItem in LineItems) {    
                      if (cartLineItem.VariantId == checkoutVariantId) {
                          cartLineItem.ID = checkoutLineItemId;
                          didUpdateID = true;
  
negative.code:         /// cart.LineItems.AddOrUpdate(product, selectedOptions, 3);
          /// \endcode
          public void AddOrUpdate(Product product, Dictionary<string, string> selectedOptions, long? quantity = null, Dictionary<string, string> customAttributes = null) {
              string variantId = VariantFromSelectedOptions(product, selectedOptions).id();
  
              if (variantId == null) {
                  throw new NoMatchingVariantException("Could not `AddOrUpdate` line item as no matching variant could be found for selected options");
  