Simple clock thread written in Python

py_thread_clock.py

#!/usr/bin/env python

from __future__ import print_function
import sys
import threading
import time
import datetime


class Clock(threading.Thread):
    def __init__(self, countdown_from=100):
        self.countdown_from = countdown_from
        self._start = None
        threading.Thread.__init__(self)

    def run(self):
        self._start = time.time()

        while True:
            time_passed = time.time() - self._start
            print('\b\b\b\b\b' + datetime.datetime.fromtimestamp(self.countdown_from - time_passed).strftime('%M:%S'), end='')
            sys.stdout.flush()
            time.sleep(0.1)
            

c = Clock(120)
c.start()