Mainly, the seems to be no way, in a dynamic language, to dynamically check if functions get the right types.

To me, this means I don't really understand the python type hinting at all, as adding hints to just one or two functions provides no value to me at all.

I assume I must be not using them usefully, as I've tried adding type hints to some projects and they just seemed to do nothing useful.

You want runtime typechecking.

See either beartype [1] or typeguard [2]. And if you're doing any kind of array-based programming (JAX or not), then jaxtyping [3].

[1] https://github.com/beartype/beartype/

[2] https://github.com/agronholm/typeguard

[3] https://github.com/patrick-kidger/jaxtyping

Type hints alone don't do this, but you can use Pydantic to accomplish what you want. In Python type hints aren't enforced anywhere at runtime. They're for a type-checker to validate your source.

https://docs.pydantic.dev/latest/concepts/validation_decorat...

How to tell me you use VScode without telling me you use VScode.