'Custom manager method is only available on the manager and not on
querysets.'

def test_manager_attributes(self):

    Person.custom_queryset_custom_manager.manager_only()
    msg = "'CustomQuerySet'    object    has    no    attribute    'manager_only'"
    with self.assertRaisesMessage(AttributeError, msg):
        Person.custom_queryset_custom_manager.all().manager_only()
