public async Task CreateRefundTest()
        {
            var args = new RefundCreateArguments
            {
                ChargeId = "some-value"
            };

            _stripe.Post(
                Arg.Is <StripeRequest <RefundCreateArguments, Refund> >(
                    a => a.UrlPath == "refunds" && a.Model == args), _cancellationToken)
            .Returns(Task.FromResult(new StripeResponse <Refund>()));
            var response = await _client.CreateRefund(args, _cancellationToken);

            response.Should().NotBeNull();
        }