nbqa black 5 notebooks

[MarcoGorelli]

xref #4095

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[codecov]

Codecov Report

Merging #4165 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4165   +/-   ##
=======================================
  Coverage   88.76%   88.76%           
=======================================
  Files          89       89           
  Lines       14083    14083           
=======================================
  Hits        12501    12501           
  Misses       1582     1582           

[AlexAndorra]

Thanks @MarcoGorelli ! Actually, for this PR, let's try a new process, to limit the number of PRs that we have to open and merge: can you make only this one PR for that one issue, but with, say, one commit per 5 notebooks?
That way, I can review every commit so that it's manageable, but we can stay on this unique PR 👌

[MarcoGorelli]

Hey @AlexAndorra ! I think that's a good suggestion!

We introduced a regression in nbqa 0.2.3 while trying to support pylint, and it's now fixed - my suggestion would be to take this PR as it is so that the nbqa version gets bumped. I'll then open a separate PR where I'll apply the formatter to 5 notebooks per commit and hopefully we can merge steps 2 and 3 of the style together before too long - does that sound good to you?

[AlexAndorra]

Yeah ok, let's go with that then 👌