Apply and ensure Black formatting

[mgaitan]

Fix for #1097

[coveralls]

Coverage decreased (-0.008%) to 64.409% when pulling 1c80f2b on mgaitan:black into 6d8db84 on Zulko:v2.

[tburrows13]

So am I correct in saying that this doesn't actually auto-format the code, it just marks PRs as unsuccessful (and therefore unmergable) if they fail?

[mgaitan]

@tburrows13 yes, you are right.

[mgaitan]

well, I don't know why the git action didn't run. It was automatic when I tried this on my fork.
It seems related to this bug https://github.community/t5/GitHub-Actions/Github-Workflow-not-running-from-pull-request-from-forked/td-p/32979.

Anyway, should be ok after merge.

[mgaitan]

And I'm wondering if wouldn't be better to implement #1081 first, removing old python version from the CI matrixes, and apply this targeting directly py36. So, we don't need another PR to apply a new black rewrite.

[tburrows13]

I agree, I intend to start a new branch today for v2.0 that removes all py27 testing. Then we can merge PRs like this one into it.

[tburrows13]

A bit later than expected, I've created #1103. When #1103 is merged into the v2 branch, you can update this PR with a fresh run of Black (without worrying about Py2.7, and then we can merge this in before anything else is merged).

I think adding something into the 'Standard workflow' in Contributing.md would be helpful as well.

Also I think the name 'sanity checks' is not very descriptive. How about 'Code Format Check' or something like that?

[mgaitan]

@tburrows13 update done.

[tburrows13]

Thanks for this. I'm happy to merge now.