def ask_yes_no(prompt):
    while True:
        answer = input(prompt + ' (y or n) ')
        if answer == 'y' or answer == 'Y':
            return True    # returning ends the function
        if answer == 'n' or answer == 'N':
            return False
        print("Answer 'y' or 'n'.")

if ask_yes_no("Do you like ice cream?"):
    print("You like ice cream!")
else:
    print("You don't like ice cream.")