1071565 update eu

This isn't done. A bunch of other things need fixing.

Posting this for feedback before I go do a lot of work that might get ditched.

feedback?
About the unreadability: line 140 confused me a bit at first because I thought it was `(key, val) if key in list_keys else val[0]` which wouldn't make sense, and I had to think a bit to realize it was `key, (val if key in list_keys else val[0])`. Maybe adding those parens to make it explicit would help.