Provider 'AnotherProvider' defines resource b as another, existing resource.

    class AnotherProvider(Provider, module=SomeModule):
        ...
        b = SomeProvider.a

But it's not a valid resource definition. A Provider's Resource cannot be
defined as an already existing Resource. An equivalent, valid definition would
be:

    b = Resource(int, ResourceKind.PRIVATE)

AnotherProvider: "src/seamful/provider/test_provider.py"
