money transfer code with all functions as C programmer profesisonal

// a function that implements the logic to transfer money between accounts
// you can use the other functions 
// you can do this in one line if you really want to
def transfer(account_from, account_to, amount):
    account_from = withdraw(account_from, amount)
    account_to = deposit(account_to, amount)

// a function that implements the logic to calculate the interest amount given a balance
def calculate_interest(balance):
    return balance * INTEREST_RATE