I suspect that this issue is caused by the python version you're running. Usually you cannot run the compiled bytecode .pyc generated from older python version with a newer python version.
If you run this command : "file decrypt.pyc".
You'll see that the python version that generates this pyc is 3.6 and you cannot run it a newer python version.
Check the python version you're running and make sure it's python 3.6.