如何将我的以下model.py文件中的defer函数应用于延迟加载字段？

Question

class Event(
OwnedModelMixin,
TimeStampedModelMixin,
RandomIDMixin,
models.Model,
 ):
    after_sunset = models.BooleanField(default=False)
    date = models.DateField(blank=True, null=True)
    notes = models.TextField(blank=True, default="")
    is_published = models.BooleanField(default=False)
    is_public = models.BooleanField(default=False)
    shabbos = models.BooleanField(default=False)
    starts = models.TimeField(blank=True, null=True)
    venue = models.ForeignKey(Venue, editable=False, blank=True, null=True)
    community = models.ForeignKey(Community, blank=True, null=True)
def __str__(self):  # pragma: no cover
    """
    Returns a reprsenative fields depending on the event type

    """
    child_events = (
        'bar_mitzvah',
        'bar_mitzvah_kiddush',
        'bris',
        'kiddush',
        'shalom_zochor',
        'vachnacht',
    )
    if self.event_type in child_events:

        return '{} on {},is_published: {}'.format(
            self.event_type,
            self.date,
            self.is_published
        )
    else:

        return '{} on {},is_published: {}'.format(
            self.event_type,
            self.date,
            self.is_published
        )

有近160个属性我没有包含在其中。但是所有属性都不是一直需要的。我想延迟加载这些属性以提高性能。由于有160个属性，有1000行。我怎么能？