I just submitted a patch to the list.extend docstring, to reflect the fact that x.extend(xrange(10)) and x.extend((2,3)) both work when x is a list. Then I went to look at the documentation and noticed it says at http://www.python.org/dev/doc/devel/lib/typesseq-mutable.html: s.extend(x) same as s[len(s):len(s)] = x (2) ... (2) Raises an exception when x is not a list object. The extend() method is experimental and not supported by mutable sequence types other than lists. Now I'm wondering what all this means. It is /not/ equivalent to the slice assignment, because list slice assignment requires a list rhs. What does this "experimental" label mean? Is my patch to the docstring wrong, in the sense that it suggests exploiting undefined behavior in the same way that the old append-multiple-items behavior was undefined? Also, I note that the table referenced above seems to be missing some right parentheses, at least on the .pop and .sort method descriptions. -Dave +---------------------------------------------------------------+ David Abrahams C++ Booster (http://www.boost.org) O__ == Pythonista (http://www.python.org) c/ /'_ == resume: http://users.rcn.com/abrahams/resume.html (*) \(*) == email: david.abrahams@rcn.com +---------------------------------------------------------------+