Set black target version to 3.9 (#19041)
Set black target version to 3.9 (#19041)


diox/olympia,wagnerand/addons-server,mozilla/addons-server,diox/olympia,diox/olympia,mozilla/addons-server,wagnerand/addons-server,mozilla/addons-server,mozilla/addons-server,diox/olympia,wagnerand/addons-server,wagnerand/addons-server