> def sequpdate(self, iterable, value=True):
> for elem in iterable:
> self[elem] = value
> return self
I'm strongly against the "return self" part. All your examples use
x = {}.sequpdate(...)
which suggests that you're really looking for a different constructor
as a class method.
--Guido van Rossum (home page: http://www.python.org/~guido/)