public BankAccount CreateBankAccount(string accountType)
        {
            BankAccount bankAccount = null;

            if (accountType.Equals(BaseAccount.GRADATION))
            {
                bankAccount = new BaseAccount();
            }

            if (accountType.Equals(GoldAccount.GRADATION))
            {
                bankAccount = new GoldAccount();
            }

            if (accountType.Equals(PlatinumAccount.GRADATION))
            {
                bankAccount = new PlatinumAccount();
            }

            return(bankAccount);
        }
        public Account Create(string numberAcc, string firstName, string secondName, string email, decimal balance = 0)
        {
            PlatinumAccount acc = new PlatinumAccount(numberAcc, firstName, secondName, email, balance);

            return(acc);
        }