# timethis.py

import time
from functools import wraps

def timethis(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        start = time.perf_counter()
        r = func(*args, **kwargs)
        end = time.perf_counter()
        print('{}.{} : {}'.format(func.__module__, func.__name__, end-start))
        return r
    return wrapper

if __name__ == '__main__':
    @timethis
    def countdown(n):
        while n > 0:
            n -= 1


    countdown(10000000)