Harmonize #6161 and #6173

[crusaderky]

No description provided.

[graingert]

previously pre-commit was failing with:

pre-commit run --all-files        
absolufy-imports.........................................................Passed
isort....................................................................Passed
pyupgrade................................................................Passed
black....................................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

distributed/tests/test_worker.py:1822:5: F821 undefined name 'assert_worker_story'
distributed/tests/test_worker.py:1849:5: F821 undefined name 'assert_worker_story'

mypy.....................................................................Passed