Hello,

I just stumbled upon black and I immediately integrated it into my workflow in PyCharm. it's really great tool.

Unfortunately I cannot reformat all of our code at once and make everything consistent, because I would be clobbering our git history and every subsequent git blame would blame me!

So I would like to have a command line switch to only reformat a part of a file, say a range of lines, e.g.

black --from-line 20 --to-line 25

so I can only reformat the code that I'm touching anyway and transform our codebase over time.