@receiver(post_save, sender=ModelWithFK)
@disable_synchro_log
def update_visits(sender, instance, created, **kwargs):
    if not created:
        # Side note: in the statement below it should be instance._prev.link in case of link change,
        # but it requires some refreshing from database (since instance._prev.link and instance.link
        # are two different instances of the same object). For this test
        instance.link.visits -= instance._prev.visits
        instance.link.save()
    instance.link.visits += instance.visits
    instance.link.save()
Update parent visits.
dataset/ETHPy150Open zlorf/django-synchro/synchro/tests.py/update_visits