[Openstack-stable-maint] Stable check of openstack/tooz for ref refs/heads/stable/train failed

Build failed. https://zuul.opendev.org/t/openstack/buildset/ffb4095e8b0c4b97ac17fa4d08a78e... - openstack-tox-docs https://zuul.opendev.org/t/openstack/build/4c44145b149f40e19182966a795a1201 : SUCCESS in 4m 27s - openstack-tox-py27 https://zuul.opendev.org/t/openstack/build/4ad45e40a1ea4cba9db74c4c9c41b030 : SUCCESS in 4m 05s - openstack-tox-py36 https://zuul.opendev.org/t/openstack/build/af5edad2bfb941f98e0f0247421c5329 : SUCCESS in 4m 55s - openstack-tox-py37 https://zuul.opendev.org/t/openstack/build/b7408de6241f4c7680cba426089f26db : FAILURE in 9m 04s