I just tested it and commented on the Github. High level summary it was ~98% perfect. I left you a couple notes with line numbers to fix minor issues but otherwise it looks awesome! I also left some notes for additional things you could add in the future if you like, but right now none of them are output in the json format (hence why I didn't mention them above when giving the json parsing instructions). I probably should have added those to the bug report ticket last night, I'll see about updating the ticket or making a new one...Could you try out my first pass and comment in the github issue tracking this (I have no sas drives and therefor no way to test myself)?
I used to live and breathe this stuff and have written several tools of my own for parsing and interpreting health data, so if you have any other questions please reach out. There's a lot of vendor proprietary stuff I wish I could share publicly to enhance the state of the tools we have available (including my own pySMART) but a lot of that stuff (particularly for SSDs!) they keep close to the chest and only share under NDA/PIA. :(