Please don't use private API. The underscore at the beginning marks the function as private.
(This has been the case for a long time; in 3.10 it is finally officially documented: https://docs.python.org/3.10/c-api/stable.html#stable )

It has been removed in alpha5; I'm afraid rc2 is too late to put it back. (Especially since we'd need to put it back as public API, as CPython doesn't need it any more.)


Please, if you see the need for any other private APIs, could you file bugs to make them public (or better, to support the use case they're needed for)? If they are useful, they should have documentation, tests, and better backwards compatibility expecations.