Python timer example

timer.py

import time

while True:
    print("How long or 'exit' when finished")
    try:
        uin = input(">> ")
    except Exception:
        break
    if uin == 'exit':
        break
    try:
        when_to_stop = abs(int(uin))
    except ValueError:
        print("Please re-enter number of seconds.")
        continue

    time_so_far = 0
    try:
        while time_so_far <= when_to_stop:
            time_left = when_to_stop - time_so_far
            print(f'{time_left}\r', end='')
            time.sleep(1.0)
            time_so_far += 1
    except KeyboardInterrupt:
        print('\nTimer aborted')