Python ejecuta cosas a ciertas a tiempo

import datetime as DT
import time

while True:
    now = DT.datetime.now()
    target = DT.datetime.combine(DT.date.today(), DT.time(hour=8))
    if target < now:
        target += DT.timedelta(days=1)

    time.sleep((target-now).total_seconds())
    # do something
Bewildered Baboon