Lots of food for thought in that article. Shows very well some of the trade offs in complexity languages have to deal with when they bring a strong type system to the table. Hence some limitations being in place... and that's why it can get into nasty metaprogramming territory quickly. This show a couple of interesting examples on how this can be mitigated although we don't have any perfect solution yet.

Type annotations become quickly complex with Python. This is in part because it's rolled out incrementally on top or existing practices. Here it collides a bit with decorators. Nice to see this hole is getting plugged though. Also nice to discover an alternative to mypy which seems a bit more precise (at least for the time being).

Interesting example of using a strong type system to avoid mistakes in code using a parsing and serialization library. The fact that it's about IMAP and I'm still traumatized by it has nothing to do with my interest in that article, really.