Thanks for the help Dirk!
Unfortunately, the new code throws an error:
Error in plugin file /omd/sites/abyss/local/share/check_mk/checks/smart: name '_' is not defined
This had me chasing a rabbit because I read “name is not defined”, but I think after rereading, it means the underscore in this line:
"title": _("Helium Level"),
However, when I remove that underscore, it comes back with the following:
Error in plugin file /omd/sites/abyss/local/share/check_mk/checks/smart: name 'metric_info' is not defined
I tried some guesses and repositioning the code within the file but I’m stuck 
.