Missing typing_extensions when building docs on Python 3.8 #3093
Description
Issue
tox -e docs
causes the following warning
WARNING: Failed guarded type import with ModuleNotFoundError("No module named 'typing_extensions'")
WARNING: Cannot resolve forward reference in type annotations of "tox.config.loader.section.Section.from_key": name 'Self' is not defined
WARNING: Failed guarded type import with ModuleNotFoundError("No module named 'typing_extensions'")
Environment
Provide at least:
- OS:
Ubuntu 20.04
Python 3.8