Dan, I don't understand what you think the code snippet shows: you're calling isclass on an object which *actually is a class* and show that it returns True. What did you expect it to return? How does the code snippet you give demonstrate a problem?

You say:

"isinstance is calling ob.__getattribute__ as a fallback instead of object.__class__.__get__"

but why do you think that is wrong, and what makes you think that object.__class__.__get__ is the right way to do it? You seem to think it is self-evident, but it isn't (at least not to me).

"It doesn't even care if the result it gets from ob.__getattribute__("__class__") isn't a type."

Should it care?