private void ProcessShipment(Shipment shipment)
        {
            shipment.Price = _pricingService.CalculatePrice(shipment);

            (decimal? price, decimal? discount) = _pricingService.CalculatePriceDiscount(shipment);

            if (discount.HasValue)
            {
                shipment.Price    = price;
                shipment.Discount = discount;

                _dataService.IncrementAccumulatedDiscounts(shipment.Date.RemoveDays(), shipment.Discount.Value);
            }

            else
            {
                shipment.Discount = 0;
            }
        }