Thanks to the updates by the HF gods, this space doesn't work anymore. Yes - HF isn't a stable code base; don't use the backend for anything important!
Writing stuff for HF feels like working in a company where some PY gurus play around with the productive system anyway they like. No announcement. No respect for user code. Breaking changes - they don't care.
I know this sucks - and if you (like me) a little miffed about that: go to the forum and open a complaint. Maybe (just maybe) this will get some attention.