Agathas.Storefront.Shopping.Model.Baskets.NonNegativeQuantity.Add C# (CSharp) Method

        public NonNegativeQuantity Add(NonNegativeQuantity quantity)
        {
            return new NonNegativeQuantity(_value + quantity._value);
        }

 public void increase_item_quantity_by(NonNegativeQuantity quantity)
 {
     _quantity = _quantity.Add(quantity);
 }