private MandateResponse CreateMandate(APIClient client)
        {
            var reference = BankAccountTester.CreateAccount(client, UserId);
            var mandate = new MandateRequest
                          {
                              BankAccount = reference,
                              UrlReturn = "http://example.com/dummy/Mandate"
                          };

            var result = client.PostMandate(mandate, UserId);
            Assert.IsNotNull(result);
            Assert.Greater(result.Id, 0);
            Assert.AreEqual(reference.Id, result.BankAccount.Id);
            return result;
        }
 public MandateResponse PostMandate(MandateRequest mandate, string userId = null)
 {
     var uri = CreateUri(userId, mandates);
     return PostAsync<MandateRequest, MandateResponse>(uri, mandate);
 }