def menu(message, accepted_vals):
    selection = input(message)
    while selection not in accepted_vals:
        print(f"Are you sure you entered {' or '.join(accepted_vals)}? Try again.")
        selection = input(message)
    return selection


accepted_vals = ["1", "2"]
selection = menu("Enter '1' for spacebar and '2' for timer: ", accepted_vals)