* Fix bug where models with a class variable using a manager defined would interfere with other managers.
- Fill in the type argument for that particular instance of the manager, rather than modifying the bases of the Manager type.
- Instantiate a new Instance from determine_proper_manager_type so The code doesn't crash under mypy-mypyc.
* Use helpers.reparametrize_instance per review comment.
* Updated ignored errors in Django test for get_objects_or_404.
- For some reason, `Manager[nothing]` is now removed from expected types.
However, I think this makes sense anyway, as Manager is a subclass of QuerySet.
- Made id_list of type Sequence[Any], rather than Any, according to mkurnikov's review.
- Removed **kwargs.
- Made returned Dict keys of type Any rather than int or str as it depends on the provided field's type.
- Added test with examples from Django docs.
- The keys are still Union[int, str] which doesn't cover all
possibilities, but it's not possible to cover without handling this in
the plugin, because the type of the Dict keys are dynamic depending on
which value for field_name you pass in.
Seth Yastrov