maxBy :: (a -> Int) -> a -> a -> a
maxBy measure a b = max $ (measure a) (measure b)

• Couldn't match expected type ‘Int -> a0’ with actual type ‘Int’
• The function ‘measure’ is applied to two arguments,
      but its type ‘a -> Int’ has only one
      In the second argument of ‘($)’, namely ‘(measure a) (measure b)’
      In the expression: max $ (measure a) (measure b)
   |
31 | maxBy measure a b = max $ (measure a) (measure b)
   |                           ^^^^^^^^^^^^^^^^^^^^^^^