printf 'import argparse
import string


S1 = f"{argparse.OPTIONAL[:9]=}"
S2 = (string.ascii_uppercase + string.ascii_lowercase)
' > test.py

python3.12 -m pip install --no-cache-dir --upgrade black --target tmpenv
for i in $(seq 1 10); do PYTHONPATH=tmpenv ./python.exe -m black --check --diff test.py; done

error: cannot format test.py: INTERNAL ERROR: Black produced code that is not equivalent to the source.  Please report a bug on https://github.com/psf/black/issues.  This diff might be helpful: /var/folders/0y/.../T/....log