∀ {α β γ : Type w} {m : Type w → Type w'} [inst : Monad m] [LawfulMonad m] [inst_2 : Std.Iterator α m β]
  [Std.Iterators.Finite α m] {f : β → γ} (it : Std.IterM m β),
  (Std.IterM.map f it).toArray = (fun x => Array.map f x) <$> it.toArray