contracts

Seems you refer to a domain specific language in the annotations. This is exactly what https://github.com/AndreaCensi/contracts does (it's an amazing project but has a very large code base). However, I wanted to achieve something similar in pure python and as compact as possible – so there are compromises (like no real symbolic calculus)

Several good ones have already been suggested, but here's a few more: - https://github.com/mahmoud/boltons : utility functions, but well documented - https://github.com/KeepSafe/aiohttp : a Python 3 async HTTP server - https://github.com/telefonicaid/di-py : a dependency injection framework - https://github.com/moggers87/salmon : a fork of Lamson (which was written by Zed) Python's internals are pretty darn open, so here's a few suggestions that push the boundaries of meta programming in Python - they're not the idiomatic code you're looking for right now, but later, when you know the best practices and you're wondering what is possible they'll be good to look at: - https://github.com/Suor/whatever : Scala's magic `_` for Python - https://github.com/ryanhiebert/typeset : Types as sets for Python - https://github.com/AndreaCensi/contracts