beartype: Unbearably fast O(1) runtime type-checking in pure Python

This looks like a powerful type-checker for Python.

Beartype brings Rust- and C++-inspired zero-cost abstractions into the lawless world of dynamically-typed Python by enforcing type safety at the granular level of functions and methods against type hints standardized by the Python community in O(1) non-amortized worst-case time with negligible constant factors.

Easy-to-use and claims to be extremely performant.