Missing follow-up change in the rest of the file.
Thanks for spotting that, I messed up during the (huge) git add -p session :p
Python 3's urlopen is equivalent to urllib2.urlopen not urllib.urlopen so I recommend importing from urllib2 instead.
This should be the same as dump_ast_matchers.py i.e.:
from urllib.request import urlopen
from urllib2 import urlopen
This still isn't done.
Sorry for the noise :-/