Removing validate brought back error reported in (D2705)
To the contrary, this should no longer be needed.
Try and rebuild your docker containers.
I usually run from time to time to take the latest versions of the swh modules pushed to pypi.org:
docker build --build-arg=CASS_DRIVER_NO_CYTHON=1 --no-cache -t swh/stack .
Also note the the launchpad lister is not upstream yet so this needs to be removed from this diff ;)