When using a virtualenv and when you just would like to improve deals extra for your virtualenv, you might want to do: all lessons and interfaces in the superclass hierarchy (e.g. see Java course is existing in classpath but startup fails with Error: Couldn't discover or load primary course) Or https://mylesbayvq.ageeksblog.com/32712519/fascination-about-uninterruptible-power-supply-pronunciation