Hi Alex! A suggestion so your expectations are aligned with what people do: You should generally never use things that aren’t documented. In most Python projects, “privateness” not indicated by the name starting with _, but by the fact that it appears at that location in the docs.

And that means that if you use something private, it can and will break without notice, and nobody did something wrong.

The best idea for something small like this here is IMHO (I’m speaking generally, I’m aware we’re AnnData’s maintainers and can control this here):

1. Ask people to export it to officially document, export and support it.
   If they do that and you don’t want to wait for it to be released you can do the following safely now:

   try:
       from new_location import thing
   except ImportError:
       from old_undocumented_location import thing

2. If they won’t export it and it’s feasible to not have the thing, you should add a test to get notified if they changed it, and create a dummy so people’s code depending on your project doesn’t break:

   try:
       from undocumented_location import thing
   except ImportError:
       thing = None  # or something else that is quick to define and doesn’t break your code

3. If they won’t export it and you need the thing, you should copy it to a location where you can depend on it existing. E.g. a new package you maintain if you need it in multiple locations.

I happen to maintain https://pypi.org/project/legacy-api-wrap/

Maybe that’s a good spot for it?