Black claims itself as uncompromising PEP8 compliant formatter, but as you can see on the .flake8, it already made some compromises. However, they are unwilling to compromise on the 4 space "guideline".
For those who got annoyed by psf#378, install black2
for black with 2 space indent with
pip install git+https://github.com/chrischoy/black2
Or in your project, you can add this line to your requirements.txt
git+https://github.com/chrischoy/black2
and
pip install -r requirements.txt
black2 <python_file.py>