Format python code with black

[pantierra]

Only ran black for better code formatting.
No code changes.

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[pantierra]

@googlebot I signed it!

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[pantierra]

As a follow up - after that had been accepted. I'm happy to do the flake8 cleanup. But maintaining those two things in parallel PRs is too much. Better to go one after another.

[avilaton]

We all want to black this but it is pretty hard to review a +23,671 −20,218 and 88 files changed. Please consider sending smaller changes.

[pantierra]

Thank you. How do you want them to be smaller? File by file?

There are no code logic changes in there at all. It is just code formatting. I know it is a lot of lines. But this is the smallest logical piece that I could come up here. Please give me clearer instructions on how to help you with this, and how you want this to become even smaller.

[davidlattimore]

One option for reviewing a change like this would be to run the formatter yourself and diff the result against this PR. That way you're independently confirming that the PR is what it says it is and that there are no additional changes.