Sort u →
  {α : Type w} →
    {m : Type w → Type w'} →
      {β : Type w} →
        [inst : Std.Iterator α m β] →
          {P : β → Prop} →
            Std.Iterators.Types.Attach α m P →
              {α' : Type w} →
                {m' : Type w → Type w'} →
                  {β' : Type w} →
                    [inst' : Std.Iterator α' m' β'] → {P' : β' → Prop} → Std.Iterators.Types.Attach α' m' P' → Sort u