3.0rc1
>>> help(list.sort)
Help on method_descriptor:

sort(...)
    L.sort(key=None, reverse=False) -- stable sort *IN PLACE*;
    cmp(x, y) -> -1, 0, 1

The last line is left over from 2.x docstring.  Since cmp keyword param
is gone (so also says LibRef: "s.sort([key[, reverse]]) sort the items
of s in place") delete it.