public async Task GetRefundsTest()
        {
            var filter = new RefundListFilter
            {
                Charge = "charge-id"
            };

            _stripe.Get(
                Arg.Is <StripeRequest <RefundListFilter, Pagination <Refund> > >(
                    a => a.UrlPath == "refunds" && a.Model == filter),
                _cancellationToken).Returns(Task.FromResult(new StripeResponse <Pagination <Refund> >()));
            var response = await _client.GetRefunds(filter, _cancellationToken);

            response.Should().NotBeNull();
        }