prop_rightId :: ArbMapSyntax String Int -> Bool
prop_rightId a = runMap (m `mappend` mempty) == runMap m
  where m = unArbSyntax a
prop_rightId :: ArbMapSyntax String Int -> Bool
prop_rightId a = runMap (m `mappend` mempty) == runMap m
  where m = unArbSyntax a
prop_rightId a = runMap (m `mappend` mempty) == runMap m
  where m = unArbSyntax a