∀ {α : Type u} {instOrd : Ord α} {β : Type v} {t : Std.DTreeMap.Internal.Impl α fun x => β} [Std.TransOrd α]
  [inst : BEq α] [Std.LawfulBEqOrd α] [inst_2 : Inhabited β],
  t.WF →
    ∀ {l : List (α × β)} {k : α},
      (List.map Prod.fst l).contains k = false →
        Std.DTreeMap.Internal.Impl.Const.get! (↑(Std.DTreeMap.Internal.Impl.Const.insertMany! t l)) k =
          Std.DTreeMap.Internal.Impl.Const.get! t k