public void appendSingleDonation(DonationTier donationTier)
 {
     if (SingleDonation.isNull())
     {
         SingleDonation = new SingleDonation();
     }
     SingleDonation.DonationTiers.Add(donationTier);
 }
 public void appendSubscriptionDonation(DonationTier donationTier)
 {
     if (SubscriptionDonation.isNull())
     {
         SubscriptionDonation = new SubscriptionDonation();
     }
     SubscriptionDonation.DonationTiers.Add(donationTier);
 }