[bootstrap] black-ify; short warning messages

4 jobs for issue-44-licence-location in 6 minutes and 42 seconds (queued for 6 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_36 #181056
docker

00:03:39

passed build_linux_37 #181057
docker

00:03:24

passed build_macosx_36 #181058
macosx

00:06:42

passed build_macosx_37 #181059
macosx

00:06:25