@slott56 mmh, maybe the design I have is bad, basically I'm writing a tool that supports plugins (which are Python classes), these plugins can be configurable (there's a base class that has the validation for the config.

I basically wanted to make sure that a plugin's configuration was properly typed without having to define the configuration type (since we are defining the configuration class already)

@patrick This is often better done with a "registery"

@myregistery.PlugIn
class YourWhatever:
...

This lets the registery object vet the plug-in for all the required features.

Further. It can involve metaclass operations to inject features.

@patrick it moves the problem out of fussing with the type system into writing a meta class that injects the needed features. The problem remains, but it might be more solvable.