public LabourCostEstimator(AllowanceFormula allowanceFormula, WageFormula wageFormula, PeriodicalFormula periodicalFormula, OnCostFormula onCostFormula)
 {
     AllowanceFormula = allowanceFormula;
     WageFormula = wageFormula;
     PeriodicalFormula = periodicalFormula;
     OnCostFormula = onCostFormula;
 }
 public LabourCostEstimator()
 {
     AllowanceFormula = new AllowanceFormula();
     WageFormula = new WageFormula();
     PeriodicalFormula = new PeriodicalFormula();
     OnCostFormula = new OnCostFormula();
 }