Sharekhan.domain.SellTransaction.CalculateShortTermTax C# (CSharp) Метод

        public virtual Price CalculateShortTermTax(BuyTransaction buyTransaction)
        {
            if (IsShortTerm(buyTransaction))
            {
                double profitOrLoss = CalculateTotalPrice(this.UnitPrice, this.Quantity) -
                                      CalculateTotalPrice(buyTransaction.UnitPrice, buyTransaction.Quantity);
                if(profitOrLoss>0)
                {
                    return new Price(0.20*profitOrLoss);
                }
            }

            return new Price(0);
        }

 public virtual Price CalculateShortTermTaxForAPairOfTransactions(BuyTransaction buyTransaction, SellTransaction sellTransaction)
 {
     return sellTransaction.CalculateShortTermTax(buyTransaction);
 }