Fix broken tests in old Python versions for #215.
Fix broken tests in old Python versions for #215.

brandm/live-py-plugin,brandm/live-py-plugin,donkirkby/live-py-plugin,donkirkby/live-py-plugin,brandm/live-py-plugin,donkirkby/live-py-plugin,donkirkby/live-py-plugin,donkirkby/live-py-plugin,brandm/live-py-plugin,brandm/live-py-plugin