I've installed wiringpi from the instructions you've given. All went well. All tests from the command line using the gpio command work well. However, my python code stops dead on the command: wpi.wiringPiSetup()

When this line runs, an error returns:
Oops: Unable to determine board revision from /proc/cpuinfo

What's the solution? I really like the wiringpi python library. It would be a shame if it doesn't work.

thanks in advance.

btw, I'm using the friendly ubuntu 18.04 desktop image on emmc. In case that matters.