internal static void ValidateWithdrawMoney(CardAccount account, decimal moneyToWithDraw)
 {
     if (account.CardCash < moneyToWithDraw)
     {
         throw new ArgumentException("Invalid withdrow value !");
     }
 } 
 internal static void ValidateWithdrawMoney(CardAccount account, decimal moneyToWithDraw)
 {
     if (account.CardCash < moneyToWithDraw)
     {
         throw new ArgumentException("Invalid withdrow value !");
     }
 }
 internal static void ValidatePin(CardAccount account , string pin)
 {
     if (account.CardPIN != pin)
     {
         throw new ArgumentException("Invalid PIN !");
     }
 }
 internal static void ValidatePin(CardAccount account, string pin)
 {
     if (account.CardPIN != pin)
     {
         throw new ArgumentException("Invalid PIN !");
     }
 }