- 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.