def test_single(self):
        self.assertOptimizesTo(
            [migrations.DeleteModel("Foo")],
            [migrations.DeleteModel("Foo")],
            exact=1,
        )
Find files eligible for deletion i.e. with link count ==1.
dataset/ETHPy150Open django/django/tests/migrations/test_optimizer.py/OptimizerTests.test_single--crossover with--dataset/ETHPy150Open openstack/ironic/ironic/drivers/modules/image_cache.py/_find_candidates_for_deletion