/// <summary>
        /// CRUD operations for inference classification.
        /// </summary>
        /// <param name="exchangeService"></param>
        public static void CreateReadUpdateDeleteInferenceClassificationOverride(ExchangeService exchangeService)
        {
            // Cleanup.
            List <InferenceClassificationOverride> overrides = exchangeService.GetInferenceClassificationOverrides();

            foreach (InferenceClassificationOverride classificationOverride in overrides)
            {
                classificationOverride.Delete();
            }

            InferenceClassificationOverride inferenceClassification = new InferenceClassificationOverride(exchangeService);

            inferenceClassification.ClassifyAs         = InferenceClassificationType.Focused;
            inferenceClassification.SenderEmailAddress = new EmailAddress()
            {
                Address = "*****@*****.**"
            };

            Assert.IsNull(inferenceClassification.Id);
            inferenceClassification.Save();
            Assert.IsNotNull(inferenceClassification.Id);

            List <InferenceClassificationOverride> inferenceClassificationOverrides =
                exchangeService.GetInferenceClassificationOverrides();

            Assert.IsTrue(inferenceClassificationOverrides.Count == 1);
            Assert.AreEqual(
                inferenceClassificationOverrides[0].ClassifyAs,
                inferenceClassification.ClassifyAs);

            Assert.AreEqual(
                inferenceClassificationOverrides[0].SenderEmailAddress.Address,
                inferenceClassification.SenderEmailAddress.Address);

            inferenceClassification.ClassifyAs = InferenceClassificationType.Other;
            inferenceClassification.Update();

            inferenceClassificationOverrides =
                exchangeService.GetInferenceClassificationOverrides();

            Assert.IsTrue(inferenceClassificationOverrides.Count == 1);
            Assert.AreEqual(
                inferenceClassificationOverrides[0].ClassifyAs,
                InferenceClassificationType.Other);

            inferenceClassification.Delete();
            Assert.IsNull(inferenceClassification.Id);
            Assert.IsNull(inferenceClassification.SenderEmailAddress);
        }