On Dec 6, 2017 20:31, "Guido van Rossum" <guido@python.org> wrote:
If the point is just to be able to test the existing API better, no PEP is needed, right? It would be an unsupported, undocumented API.

In the short term that's one major goal.  In the long term the functionality provided by the PEP is a prerequisite for other concurrency-related features, and targeting 3.8 for that is fine. :)