A bit tangential, but wanted to point out how modern Python gets surprisingly close (in the pragmatic sense) to Rust in terms of replacing tests with type-level

A bit tangential, but wanted to point out how modern Python gets surprisingly close (in the pragmatic sense) to Rust in terms of replacing tests with type-level correctness checks (proofs?). I realise you used Python merely as an example. For example, Python can do structural pattern matching with exhaustiveness checking on the type level nowadays. It lacks discriminated unions, the ultimate secret ingredient, so will keep lagging behind in that area sadly.