Similarly, I'm amazed by Pycharm (IDE), which supports pretty good inferred type hints from debugging and static code anlysis, btw. Makes writing code a lot easier. Looking forward to trying MonkeyType, it seems awesome for lager projects.
Pycharm relies on pre-generated annotations as well, they're just built-in - it's not as magically trace-y and infer-y as it might seem at a casual glance.
