∀ {α : Type w} {m : Type w → Type w'} [inst : Monad m] [LawfulMonad m] {β : Type w} [inst_2 : Std.Iterator α m β]
  [Std.Iterators.Finite α m] {f : β → Bool} {it : Std.IterM m β},
  (Std.IterM.filter f it).toList = List.filter f <$> it.toList