def _ensure_required_fields(cls):
"""
Every ``Group`` model requires a foreign key to the ``Subsession``
model of the same app.
"""
subsession_model = '{app_label}.Subsession'.format(
app_label=cls._meta.app_label)
subsession_field = djmodels.ForeignKey(subsession_model,
on_delete=models.CASCADE)
ensure_field(cls, 'subsession', subsession_field)
add_field_tracker(cls)
def _ensure_required_fields(cls):
add_field_tracker(cls)
