tent/cache config read

I see no coverage report for this PR (shouldn't it come? or may be you would need to enable it on your repo...?)... this looks like a new logic? is there anything to document a bit more ? e.g. this else, so if not dict -- what it would be? if None -- make it explicit elfi and then in else throw exception since s2 here is just not used and I want to avoid some side-effects