def expire_tags(self, now: datetime.datetime | None = None):
        """Expire all tags in an object if the expiration date is due."""
        if not now:
            now = datetime.datetime.now(tz=datetime.timezone.utc)
        for i, tag in enumerate(self.tags):
            if tag.expires is None:
                continue
            self.tags[i].fresh = tag.expires > now
        self.save()
Expire all tags in an object if the expiration date is due.
core/schemas/model.py