@Override
    public Num calculate(Position position, int currentIndex) {
        return this.calculate(position);
    }
@Test
    public void calculateSingleTradeCost() {
        // Price - Amount calculation Test
        Num price = DoubleNum.valueOf(100);
        Num amount = DoubleNum.valueOf(2);
        Num cost = transactionModel.calculate(price, amount);

        assertNumEquals(DoubleNum.valueOf(2), cost);
    }