public BasketServiceAdapter(BasketRepository repository, BasketDiscountPolicy discountPolicy)
        {
            if (repository == null)
            {
                throw new ArgumentNullException("repository");
            }
            if (discountPolicy == null)
            {
                throw new ArgumentNullException("discountPolicy");
            }

            this.repository = repository;
            this.discountPolicy = discountPolicy;
        }