readLemmas :: [SExpr] -> Map.Map String [String]
readLemmas =
  foldr (\ (node, sen) -> Map.insertWith (++) node [sen]) Map.empty
  . mapMaybe findState
readLemmas :: [SExpr] -> Map.Map String [String]
readLemmas =
  foldr (\ (node, sen) -> Map.insertWith (++) node [sen]) Map.empty
  . mapMaybe findState
readLemmas =
  foldr (\ (node, sen) -> Map.insertWith (++) node [sen]) Map.empty
  . mapMaybe findState