We have a customer who requires the use of the "read_defaults_file" feature of PyMySQL but also including the use of the "host" key being present in the file and not the URL. Upstream, a bug in PyMySQL 0.6.7 is fixed as of https://github.com/PyMySQL/PyMySQL/issues/389 which resolves this issue. Since there are no further PyMySQL 0.6.x versions, and RHOS 11 and everyone else are on PyMySQL 0.7.9, it would be safer to rebase to 0.7.9, rather than trying to backport the issue, and/or moving to an earlier 0.7.x version.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:2824