∀ {α : Type u} {β : α → Type v} {cmp : α → α → Ordering} {t : Std.DTreeMap.Raw α β cmp} [Std.TransCmp cmp]
  [inst : Std.LawfulEqCmp cmp],
  t.WF →
    ∀ {l : List ((a : α) × β a)} {k k' : α} (k_eq : cmp k k' = Ordering.eq) {v : β k} [inst_1 : Inhabited (β k')],
      List.Pairwise (fun a b => ¬cmp a.fst b.fst = Ordering.eq) l → ⟨k, v⟩ ∈ l → (t.insertMany l).get! k' = cast ⋯ v