-- GHCi seems to crash if I call this on a "showInstanceAsGraph" result without
-- having previously forced evaluation of the matching.
goGraph :: (Show a, Show b, Graph gr) => gr a b -> IO ()
-- GHCi seems to crash if I call this on a "showInstanceAsGraph" result without
-- having previously forced evaluation of the matching.
goGraph :: (Show a, Show b, Graph gr) => gr a b -> IO ()