The post-merge build i s currently failing (see e.g. this) as a result of the repo running the tox-py27-coverage-publish job.
Since we've updated to py37 this job should be updated to reflect this.
Per zuul/layout.yaml we are the only ones using this job so it should be safe to replace it in jjb/python-jobs.yaml and then point zuul/layout.yaml to the new one.