private TransactionResponse ExecRestTransaction(string uri, string jsonData, string sessionToken, string method, string txnType)
        {
            TransactionResponse response      = new TransactionResponse();
            HttpClientApi       httpClientApi = new HttpClientApi();

            string restResponse = httpClientApi.ProcessRestTransaction(uri, jsonData, sessionToken, httpMethod: method);

            if (httpClientApi.httpStatus == System.Net.HttpStatusCode.OK && httpClientApi.exceptionStatus == "NONE")
            {
                VelocityTxnResponse apiResp = JsonConvert.DeserializeObject <VelocityTxnResponse>(restResponse);
                response = apiResp.GetTransactionResponse();
            }
            else
            {
                response.ErrorMessage = string.Format("Error processing {0} on device {1} : Result: {2} : Detail: {3}", txnType, uri, httpClientApi.statusCode, httpClientApi.exceptionData);
                response.IsError      = true;
            }

            return(response);
        }
        VelocityTxnResponse fromJson(string json)
        {
            VelocityTxnResponse apiTxnResponse = JsonConvert.DeserializeObject <VelocityTxnResponse>(json);

            return(apiTxnResponse);
        }