Attaching a patch that takes the option of simply dropping the python3-trollius package.
diff -Nru python-trollius-2.1~b1/debian/changelog python-trollius-2.1~b1/debian/changelog --- python-trollius-2.1~b1/debian/changelog 2016-05-20 07:36:53.000000000 +1200 +++ python-trollius-2.1~b1/debian/changelog 2017-07-13 14:49:30.000000000 +1200 @@ -1,3 +1,9 @@ +python-trollius (2.1~b1-5) unstable; urgency=medium + + * Stop building python3-trollius. (Closes: #867771) + + -- Michael Hudson-Doyle <michael.hud...@ubuntu.com> Thu, 13 Jul 2017 14:49:06 +1200 + python-trollius (2.1~b1-4) unstable; urgency=medium * d/rules: Changed UPSTREAM_GIT protocol to https diff -Nru python-trollius-2.1~b1/debian/control python-trollius-2.1~b1/debian/control --- python-trollius-2.1~b1/debian/control 2016-05-20 07:36:53.000000000 +1200 +++ python-trollius-2.1~b1/debian/control 2017-07-13 14:48:48.000000000 +1200 @@ -33,14 +33,3 @@ Linux, Mac OS X, FreeBSD and OpenIndiana. . This package contains the Python 2.x module. - -Package: python3-trollius -Architecture: all -Depends: ${misc:Depends}, - ${python3:Depends}, -Description: port of the Tulip project on Python 2.7 - Python 3.x - Trollius is a portage of the Tulip project (asyncio module, PEP 3156) on - Python 2. Trollius works on Python 2.6-3.4. It has been tested on Windows, - Linux, Mac OS X, FreeBSD and OpenIndiana. - . - This package contains the Python 3.x module.