Martijn Pieters added the comment: Sorry, that should have read "the forward references section of PEP 484".
The section uses this example: # File models/a.py from models import b class A(Model): def foo(self, b: 'b.B'): ... # File models/b.py from models import a class B(Model): def bar(self, a: 'a.A'): ... # File main.py from models.a import A from models.b import B which doesn't fail because the forward references are not being tested until after all imports have completed; creating a Union however triggers a subclass test between the different types in the union. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue26477> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com