Mention st g@ returns the number of times the group @g@ has been
--   mentioned
lastMentions :: RefHistory -> DiscourseUnit -> Int
lastMentions st k = Map.findWithDefault 0 k (rhCount st)

-- | Tru
lastMentions :: RefHistory -> DiscourseUnit -> Int
lastMentions st k = Map.findWithDefault 0 k (rhCount st)
lastMentions st k = Map.findWithDefault 0 k (rhCount st)