dir(obj) is only confused if it returns attributes that are not found in obj.__dict__ (aka virtual attributes).

For these virtual attributes, setting __objclass__ solves the problem.

Armin, when you say it's a workaround do you mean __objclass__ itself, or the way Ronald and I are using it?  It looks like Ronald is using it the way it was intended (on a descriptor), although I may be abusing it by putting it on an Enum member.