Python Standard Library
PyAnnotate
monkeytype
http://mypy-lang.blogspot.com/2017/11/dropbox-releases-pyannotate-auto.html
The -w flag means "go ahead, update the file":
$ pip install pyannotate $ pyannotate -w FILE
https://instagram-engineering.com/let-your-code-type-hint-itself-introducing-open-source-monkeytype-a855c7284881
$ pip install monkeytype $ monkeytype run runtests.py $ monkeytype stub some.module $ monkeytype apply some.module