Multi is the default api for methods, it is not necessary to explicitly
decorate methods with it, adds clutter and most people use it because
they see that the rest of the code uses it.
Done with `find . -type f -name '*.py' | xargs sed -i '/@api.multi/d'`
I clearly missed some bits in 01e3514147
as _get_access_token was still using urllib.Request despite that
import having been removed.
Fix it up by properly converting it to requests.
Fixes#21544
In Python 3, all of these were "consolidated" under urllib(.request,
.parse, .errors) which is inconvenient.
Since we already have hard dependencies on requests and
werkzeug(.urls, which is a backport of Python 3's unicode-aware
urllib.parse) migrate *everything* to that.
A sticking point is urllib2.URLError, those were (mostly) replaced by
the slightly more general IOError which URLError extends.
Adrian Torres