[issue32932] better error message when __all__ contains non-str objects

[Xiang Zhang]

Change by Xiang Zhang <angwerzx at 126.com>:


----------
keywords: +patch
pull_requests: +5624
stage: needs patch -> patch review

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32932>
_______________________________________