David Miguel Susano Pinto added the comment:
I have just found out that commit 2438cdf0e93 which added the winmode argument
and the documentation for it disagree. Documentation states that default is
zero while the real default in code is None.
I have opened PR 19167 on github to address it
New submission from David Miguel Susano Pinto :
set union, intersection, difference methods accept any non-zero number of sets
and return a new set instance, like so:
>>> a = set([1, 2])
>>> b = set([1, 3])
>>> c = set([3, 5])
>>> set.unio