[docs] [issue17422] language reference should specify restrictions on class namespace

Change by Caleb Donovick <donovick@cs.stanford.edu>: ---------- pull_requests: +18041 stage: needs patch -> patch review pull_request: https://github.com/python/cpython/pull/18682 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue17422> _______________________________________