formatting: run black version 19.10b0 on the codebase...
formatting: run black version 19.10b0 on the codebase
The latest version of black is out and contains the change we needed. So we can
start using it now.
note: `test-check-format.t` will complains about this changes because it still
use `grey` and need to be migrated to `black`. See next changesets for this.
