One deposit, one withdrawal
Input
process_account(100, [50], [25])
Output
125
Start at 100, deposit 50 => 150, withdraw 25 => 125, return 125.
Full lesson preview
Add a Method to a Class
Extend a class by adding a method that modifies instance state.
Python practice10 minClasses & Objects FundamentalsBeginnerLast updated April 7, 2026
Problem statement
The BankAccount class has a deposit method but is missing withdraw. Implement the withdraw method that subtracts the given amount from the account balance. Then complete process_account(initial, deposits, withdrawals) to:
- Create a BankAccount with the given initial balance.
- Apply each deposit in the deposits list using deposit.
- Apply each withdrawal in the withdrawals list using withdraw.
- Return the final balance (may be negative if withdrawals exceed funds).
This exercise focuses on adding instance methods and using them to change object state.
Task
Implement a missing method on a class and use it through a helper function that performs multiple operations.
Examples
Input format
Three parameters: initial (int), deposits (list of ints), withdrawals (list of ints).
Output format
An int representing the final account balance.
Constraints
Amounts are integers. Withdrawals may exceed balance; allow negative balances.
Samples
Sample 1
Input
process_account(0, [10, 20], [5])
Output
25
0 + 10 + 20 - 5 = 25