The last 3 years or so I've been working on a decompiler, and it is like a compiler in complexity, engineering, and testing. But different.
In https://github.com/rocky/python-uncompyle6/wiki/pycdc-compared-with-uncompyle6 I compare two Python decompilers which I submit for your review. Of course, since I am working on one, I am not impartial. So I rely on others here to set the story straight.