tl;dr: current docker image hasn’t got the hex util xxd (but should).
The reason the shell script (called within the python script - thus the py stacktrace) exits is it can’t locate xxd on its PATH (for some zip magic). The tag got pushed onto 3 days ago, probably not from that Dockerfile or it is erroring somewhere in the apt-get and nobody noticed.
You can run the image interactively and see for yourself. What to do? build the Dockerimage in the linked repo give it a :local tag and change that in your invocation.
missing git ref: I prefered the v1-t branches, not the build tags. Just taking whatever is at that moment in the tip
If you built AOSP before, I’d forgo the docker method, much more flexible