Format python code with black

[xamanu]

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

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project (if not, look below for help). Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please visit https://cla.developers.google.com/ to sign.

Once you've signed (or fixed any issues), please reply here with @googlebot I signed it! and we'll verify it.

---

What to do if you already signed the CLA

Individual signers

• It's possible we don't have your GitHub username or you're using a different email address on your commit. Check your existing CLA data and verify that your email is set on your git commits.

Corporate signers

• Your company has a Point of Contact who decides which employees are authorized to participate. Ask your POC to be added to the group of authorized contributors. If you don't know who your Point of Contact is, direct the Google project maintainer to go/cla#troubleshoot (Public version).
• The email used to register you as an authorized contributor must be the email used for the Git commit. Check your existing CLA data and verify that your email is set on your git commits.
• The email used to register you as an authorized contributor must also be attached to your GitHub account.

ℹ️ Googlers: Go here for more info.

[xamanu]

@googlebot I signed it!

[googlebot]

CLAs look good, thanks!

ℹ️ Googlers: Go here for more info.

[xamanu]

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.

[xamanu]

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.