Set: pp::colors
  Set: pp::unicode
  Assumed: N
  Assumed: a
Error (line: 3, pos: 14) type expected, got
    a
Error (line: 4, pos: 6) function expected at
    a a
  Assumed: f
Error (line: 6, pos: 6) type mismatch at application
    f (λ x : N, x)
Function type:
    N → N
Argument type:
    (λ x : N, x) : N → N