Exercise : BankAccount transactionFee

• Add a double field to the BankAccount class named transactionFee that represents an amount of money to deduct every time the user withdraws money. The default value is $0.00, but the client can change the value. Deduct the transaction fee money during every withdraw call (but not from deposits).
• Make sure that the balance cannot go negative during a withdrawal. If the withdrawal (amount plus transaction fee) would cause it to become negative, don't modify the balance value at all.
• Test your solution to this problem in Practice-It.