tick.py

from time import time, sleep
from itertools import count


def tick(seconds, n=None, timefunc=time.time):
    start = timefunc()
    yield start
    gen = count(1) if n is None else range(1, n)
    for i in gen:
        while True:
            now = timefunc()
            if now-start >= i*seconds:
                yield now
                break
            sleep((start+i*seconds-now)*0.5)  # adaptive waiting