private static void deleteCertificate(IoTDAClient client)
        {
            DeleteCertificateRequest req = new DeleteCertificateRequest
            {
                CertificateId = "9dc7eed5-00e7-4ef1-a1cc-9fb43ad1d767",
                InstanceId    = "1a7ffc5c-d89c-44dd-8265-b1653d951ce0"
            };

            try
            {
                var resp = client.DeleteCertificate(req);
                Console.WriteLine(resp.HttpStatusCode);
            }
            catch (RequestTimeoutException requestTimeoutException)
            {
                Console.WriteLine(requestTimeoutException.ErrorMessage);
            }
            catch (ServiceResponseException clientRequestException)
            {
                Console.WriteLine(clientRequestException.HttpStatusCode);
                Console.WriteLine(clientRequestException.ErrorCode);
                Console.WriteLine(clientRequestException.ErrorMsg);
            }
            catch (ConnectionException connectionException)
            {
                Console.WriteLine(connectionException.ErrorMessage);
            }
        }