public async Task UpdateAsync_Success()
        {
            PreApprovalCreateRequest request = BuildCreateRequest();
            PreApproval createdPreApproval   = await client.CreateAsync(request);

            await Task.Delay(1000);

            PreApprovalUpdateRequest updateRequest = BuildUpdateRequest();
            PreApproval preapproval =
                await client.UpdateAsync(createdPreApproval.Id, updateRequest);

            Assert.NotNull(preapproval);
            Assert.Equal(updateRequest.ExternalReference, preapproval.ExternalReference);
        }
        public void Update_Success()
        {
            PreApprovalCreateRequest request = BuildCreateRequest();
            PreApproval createdPreApproval   = client.Create(request);

            Thread.Sleep(1000);

            PreApprovalUpdateRequest updateRequest = BuildUpdateRequest();
            PreApproval preapproval =
                client.Update(createdPreApproval.Id, updateRequest);

            Assert.NotNull(preapproval);
            Assert.Equal(updateRequest.ExternalReference, preapproval.ExternalReference);
        }