f.hs

    -- | Turn a redundancy group into an inventory.ini block. We assume it's already grouped, so we just look at the first
    -- element to figure out the redundancy group label.
    rdGroup :: NE.NonEmpty HostMeta -> Maybe (Doc ())
    rdGroup (x NE.:| xs) = case hostRdGrp x of
      Nothing -> Nothing
      Just label -> Just $ (vsep (brackets (rdGrpLabel label)
                                 : (toHost rf `mapMaybe` (x : xs))))