    • Couldn't match type ‘Data.Set.Internal.Set Int’ with ‘Int’
      Expected: Int -> [Int]
        Actual: Data.Set.Internal.Set Int -> [Int]
    • In the second argument of ‘(.)’, namely ‘toList’
      In the expression: head . toList
      In an equation for ‘test’: test = head . toList
   |
83 | test = head . toList
   |               ^^^^^^
