We believe the error is caused by a bad wheel for lxml 3.7.0 that was pushed today to PyPi Thanks to everyone working together on this issue in #openstack-infra ! A patch is proposed to blacklist that release and we are testing it now. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20161222/be2d283d/attachment-0001.html>