@receiver(post_save, sender=Card)
def create_practice_objects_for_new_card(sender,update_fields, **kwargs):
    perm_users = get_users_with_perms(kwargs['instance'].deck)
    for user in perm_users:
        practice = Practice(item = kwargs['instance'], user = user)
        if Practice.objects.filter(object_id = kwargs['instance'].ID, user=user).count() == 0:
            practice.save()
A deferred from the Proxy can be cancelled, disconnecting
dataset/ETHPy150Open DummyDivision/Tsune/deckglue/models.py/create_practice_objects_for_new_card--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/web/test/test_xmlrpc.py/XMLRPCTestCase.test_cancel