∀ {α : Type u_1} {m : Type u_1 → Type u_2} {β : Type u_1} [inst : Monad m] [inst_1 : MonadAttach m] [Std.Iterator α m β]
  {it : Std.IterM m β} {P : β → m (ULift.{u_1, 0} Bool)} {dropping : Bool},
  Std.IterM.Intermediate.dropWhileM P dropping it =
    Std.IterM.Intermediate.dropWhileWithPostcondition (Std.Iterators.PostconditionT.attachLift ∘ P) dropping it