if p ∧ q then f x else y : N
t10.lean:14:6: error: type mismatch at application
  ite (p ∧ q) q
term
  q
has type
  B
but is expected to have type
  N
sorry : ?M_1
[x, y, z, x, y, y] : list
[x] : list
[] : list
