public DonationEngine(ITaxRateStorage taxRateStore, 
              IGiftAidCalculator calculator,
              ISupplementCalculator supplementConfiguration)
 {
     _taxRateStore = taxRateStore;
     _calculator = calculator;
     _supplementConfiguration = supplementConfiguration;
 }
 public DonationEngine(ITaxRateStorage taxRateStore,
                       IGiftAidCalculator calculator,
                       ISupplementCalculator supplementConfiguration)
 {
     _taxRateStore            = taxRateStore;
     _calculator              = calculator;
     _supplementConfiguration = supplementConfiguration;
 }