@property
    def total(self):
        return self.subtotal if not self.tax else self.subtotal + self.total_tax
Testing the `Collect` aggregate.
dataset/ETHPy150Open bread-and-pepper/django-brookie/brookie/models.py/Invoice.total--crossover with--dataset/ETHPy150Open django/django/tests/gis_tests/relatedapp/tests.py/RelatedGeoModelTest.test_collect