TYP: pandas/core/frame.py (easy: Axis/Level)
- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Splitting this away from #38416
looks fine. merge master and ping on green. Rebased + green thanks 