Big O of sets

[Tony Meyer]

Alex Martelli's excellent Nutshell book has a handy little section outlining
the Big O notation of various common Python operations (x in dict and
list.append(x), for example).  Can anyone point me to equivalents for the
Python 2.3 sets.[Immutable]Set operations?

I know that I could figure these myself from either timing or reading the
code, but it'd be nice if someone's already done this :)  Either googling
can't find it, or (more likely), I'm not thinking of the right search terms.

In particular, I'm interested in intersection, union and > (proper subset),
and of ImmutableSets, rather than Sets.

Thanks!

=Tony Meyer