[sevensor]

> you still can't really rely on it for much

And yet, type annotations in Python are a tremendous improvement and they catch a lot of bugs before they ever appear. Even if I could rely on the type system for nothing it would still catch the bugs that it catches. In fact, there are places where I rely on the type system because I know it does a good job: pure functions on immutable data. And this leads to a secondary benefit: because the type checker is so good at finding errors in pure functions on immutable data, you end up pushing more of your code into those functions.