Thanks for the report. I couldn't find any CPython related stack trace in the traceback and this looks like a custom validation error raised by salt. Can you please add a simple reproducer without any external dependencies to reproduce this without which I propose to close this as third-party.

The Python version in GitHub issue report is Python 2.7.5 which is very old so can you please test this on Python 2.7.15 under different kernels as in the GitHub issue and perhaps add the traceback here for the same with a pure python reproducer without dependencies.