
mc20.hs:14:31:
    No instance for (Ord Unorderable)
      arising from a use of `groupWith'
    Possible fix: add an instance declaration for (Ord Unorderable)
    In the expression: groupWith
    In a stmt of a monad comprehension: then group by x using groupWith
    In the expression:
      [() | x <- [Gnorf, Brain], then group by x using groupWith]
