private void AddIncomeDeduction()
        {
            var incomeDeduction = new FlatDeduction(0.25);

            incomeDeduction.Description = "Income Tax: flat rate of 25% over the gross salary";
            AddDeduction(incomeDeduction);
        }
        private void AddPensionDeduction()
        {
            var pensionDeduction = new FlatDeduction(0.02);

            pensionDeduction.Description = "Compulsory Pension Contribution: 2% applied to the gross salary";

            AddDeduction(pensionDeduction);
        }