19.3.0
Move test helpers into an utils module
Split cmp into eq and order (#574)
Fix default values that are not comparable with '==' (#586)
Check type of set_run_validators' arg
Implement attr.converters.default_if_none (#414)
Fade to Black (#392)
Be consistent in calling slotted classes slotted
Add default_role for Sphinx. (#571)
Rename _version.py into _version_info.py
Fix some typing issues (#581)