CLN/REF: indexing typing, prune unreachable branches
still would like to move to a unified pandas/core/indexing/..... structure sooner rather than later ok to merge, though if you want to split the setting routine I think might be helpful here. > though if you want to split the setting routine I think might be helpful here.

will do in next round.  lots of balls (branches) in the air > > though if you want to split the setting routine I think might be helpful here.
> 
> will do in next round. lots of balls (branches) in the air

k thanks