A great Marshal decompiler python2.7
$ apt install python2 git
$ git clone https://github.com/kapten-kaizo/mardis
$ cd mardis
$ python2 -m pip install xdis==5.0.11
$ python2 -m pip install uncompyle6==3.7.4
$ python2 setup.py install
See https://youtu.be/0jWGC5AbF2I for more