Comment 3 for bug 1760621

This has already been fixed upstream. It's a Python indenting issue.
https://github.com/Guake/guake/commit/f8699b4be6c058fd58a33a1d783cd404e9076b0e

In current 18.04 package (guake 3.0.5-1), it's this file (line 1420):
/usr/lib/python3/dist-packages/guake/guake_app.py