public void DeleteInvestment(InvestmentInGoal investment)
 {
     if (investment != null)
     {
         _investmentsInGoal.Remove(investment);
     }
 }
 public void AddInvestment(InvestmentInGoal investment)
 {
     if (investment != null)
     {
         _investmentsInGoal.Add(investment);
     }
 }