@roland @djsumdog @mk @RedTechEngineer Well, Python 3 was a big change. All of my Ruby 1.8(!!) code still works in 3.4, most PHP stuff is the same, but in Python's case, it's got less to do with code, it's a coordination effort: lift the world without moving it.

Jython, for example, is still only compatible with Python 2.7. People that use Jython still have to write 2.7 code: if you want your Python code to talk to Scala, you have to write code that works on Python 2. So you write a library that bridges some code written in Java with some code written in Python and then someone else's Scala depends on it, you can't just wave a wand.