private void ValidateMerchantId()
        {
            StringValidator validator = new StringValidator(nameof(_configuration.MerchantId), _configuration.MerchantId);

            validator.IsNotNullOrWhiteSpace();
            validator.IsNotLongerThan(15);
            validator.IsAlphanumeric();
        }
        private void ValidateTransactionReference()
        {
            StringValidator validator = new StringValidator(nameof(_request.TransactionReference), _request.TransactionReference);

            validator.IsNotNullOrWhiteSpace();
            validator.IsNotLongerThan(32);
            validator.IsAlphanumeric();
        }
        private void ValidateReturnUrl()
        {
            StringValidator validator = new StringValidator(nameof(_request.ReturnUrl), _request.ReturnUrl);

            validator.IsNotNullOrWhiteSpace();
            validator.DoesNotContainSeparator();
            validator.IsNotLongerThan(512);
        }
        private void ValidateAutomaticResponseUrl()
        {
            if (_request.AutomaticResponseUrl == null)
            {
                return;
            }

            StringValidator validator = new StringValidator(nameof(_request.AutomaticResponseUrl), _request.AutomaticResponseUrl);

            validator.DoesNotContainSeparator();
            validator.IsNotLongerThan(512);
        }
        private void ValidateCaptureMode()
        {
            if (string.IsNullOrEmpty(_request.CaptureMode))
            {
                return;
            }

            StringValidator validator = new StringValidator(nameof(_request.CaptureMode), _request.CaptureMode);

            validator.IsNotWhiteSpace();
            validator.IsNotLongerThan(20);
            validator.IsAlphanumeric();
        }
        private void ValidateOrderId()
        {
            if (string.IsNullOrEmpty(_request.OrderId))
            {
                return;
            }

            StringValidator validator = new StringValidator(nameof(_request.OrderId), _request.OrderId);

            validator.IsNotWhiteSpace();
            validator.IsNotLongerThan(32);
            validator.IsAlphanumeric();
        }