Hi all, I've been working on a PR to add static typing to the beam python sdk for the past 4 months or so. This has been an epic journey which has required chasing down numerous fixes across several other projects (mypy, pylint, python-future), but the mypy tests are now passing!
I'm not sure how much convincing I need to do with this group on the benefits of static typing, especially considering the heavy Java influence on this project, but for those who are curious, there's some good info here: https://realpython.com/python-type-checking/#pros-and-cons. Suffice it to say, it's a game changer for projects like Beam (large code base, high level of quality, good testing infrastructure), and it dovetails perfectly into the efforts surrounding pipeline type analysis and serialization. Anecdotally speaking, all of the developers I've worked with who were originally resistant to static typing in python ("it's ugly!" "it's not pythonic!") have changed their tune and fully embraced it because of the time that it saves them every day. More details over at the PR: https://github.com/apache/beam/pull/9056 I look forward to your feedback! -chad
