there's also pytyp, which is pure-python (inefficient) but integrates with ABCs as well as annotations. no-one uses it, as far as i know, but i thought i'd thr

there's also pytyp, which is pure-python (inefficient) but integrates with ABCs as well as annotations. no-one uses it, as far as i know, but i thought i'd throw it out there in case you were interested - http://www.acooke.org/pytyp/ http://www.acooke.org/pytyp/ i also have a vague memory of there being discussions on the python ideas list (which i don't read regularly). you might look there.