> Nope.  You are welcome to give more meaningful names to different combinations of powers of two.

Yes, you're correct here, but what about output? Do all relevant bits have to be named separately? And will the output always talk about separate bits? We have talked about this. If I give meaningful name to 1, 3, 4 and 6, but not to 2, is it supported? And is the repr of 7 an implementation detail, or is it specified?

One more question: in the docs, you say 

> otherwise, all members evaluate as :data:`True`.

I would like you to reconsider the case of `.0` (.NONE in my terminology). Many other things in the interface (e.g. `in` operator) are modelled as if flags instance were just a container (set, in fact) of bits. In that case, empty set _should_ be false. Otherwise, this will be a weird exception to the usual container semantics.