Not really, the implementations are different enough that it would be
*really* hard to keep common code.  The two parallel each other in a way
that is visually easy to translate but hard to do through real
refactoring.  For the most part, both code bases have historically been
very stable, so double maintenance hasn't been much of an issue.  My
last post was meant to suggest the cleanest way to do the Py3.0
string-->unicode switch modeling the set changes after those in dicts.  

FWIW, the reason that I put effort in to keeping the code as parallel as
possible was that it would save us mental clock cycles -- understanding
one implementation gives you most of the other for free.