I don’t want classes and constructors at all. I want instances, objects which have typed attribute access, so your description of A SimpleNamespace is more like a dict with attribute access instead of item access. sounds perfect.
Right now I can create a dataclass and create a single instance of it. It’s verbose, error prone and it’s slower runtime than SimpleNamespace.
So this is why I asked if SimpleNamespace attribute can be derived from the constructor types using some generics. If I can express the same with my own class that’s good as well.