The tooz gate is currently blocked on https://bugs.launchpad.net/python-tooz/+bug/1808046 which seems to have been introduced with grpcio 1.16.0. I need to raise that issue with the grpc folks, but in the meantime should we block the problematic versions? grpcio isn't currently in g-r and I can't remember what our policy on transitive dependencies is, so I thought I'd solicit opinions. Thanks. -Ben