def _add_tummytime_entry(self):
        """
        Add a Tummy time entry and advance self.time.
        :returns:
        """
        milestone = ""
        if choice([True, False]):
            milestone = self.faker.sentence()
        start = self.time + timedelta(minutes=randint(1, 60))
        end = start + timedelta(minutes=randint(0, 10), seconds=randint(0, 59))
        if (end - start).seconds < 20:
            end = start + timedelta(minutes=1, seconds=30)

        if end < self.time_now:
            instance = models.TummyTime.objects.create(
                child=self.child, start=start, end=end, milestone=milestone
            )
            instance.save()
            self._add_tags(instance)
        self.time = end

        Add a Tummy time entry and advance self.time.
        :returns:
        
babybuddy/management/commands/fake.py