@property
    def effective_start(self):
        if self.pk and self.end_recurring_period:
            occ_generator = self._occurrences_after_generator(self.start)
            try:
                return next(occ_generator).start
            except __HOLE__:
                pass
        elif self.pk:
            return self.start
        return None
dataset/ETHPy150Open llazzaro/django-scheduler/schedule/models/events.py/Event.effective_start