Simplify test assertion to satisfy linter

greg/tests/models/test_sponsor.py

@@ -49,7 +49,7 @@ def test_add_muliple_sponsors_to_unit(sponsor_foo, sponsor_bar, unit1, unit2):
     assert list(sponsor_foo.units.all()) == [unit1]
     assert list(sponsor_bar.units.all()) == [unit1]
     assert list(Sponsor.objects.filter(units=unit1.id)) == [sponsor_foo, sponsor_bar]
-    assert list(Sponsor.objects.filter(units=unit2.id)) == []
+    assert not list(Sponsor.objects.filter(units=unit2.id))
 
 
 @pytest.mark.django_db