Nit: I think the presentation of the 12-row table in msg310830 can be improved, e.g. by putting the legend for add* closer and/or giving add* a clearer name, and by splitting it into three 4-row tables. Currently the legend comes before all the other tables, and those aren't very useful (they're all the same, except for 'order', and the exception there is better explained in text).

But that's a matter for whoever writes the docs. As a spec it is unambiguous. On python-dev I've just posted that I support this version.