black

Black reformats Python files deterministically using sensible defaults, with project settings in pyproject.toml. It validates output against the original AST (unless --fast), claims PEP 8 compliance, and is MIT-licensed with docs on ReadTheDocs and Discord support. Install via pip install black (Python 3.10+), with jupyter extra for notebooks and standalone PyInstaller binaries available. Run as `black {source}` or `python -m black {source}`. Adopted by open-source projects including pytest, tox, Django, pandas, Poetry, Home Assistant, and Zulip, plus organizations like Dropbox, Lyft, Mozilla, and Tesla. Quotes from Mike Bayer, Kenneth Reitz, and others praise its ability to eliminate formatting debates.