On Wed, 17 Oct 2007 13:41:06 +0200, Hrvoje Niksic wrote: > The current implementation of += uses __add__ for addition and __iadd__ > for addition that may or may not be in-place. I'd like to know the > rationale for that design. Everything you need is in the PEP: http://www.python.org/dev/peps/pep-0203/ -- Steven.