∀ {α : Type u} {β : α → Type v} {cmp : α → α → Ordering} {t : Std.DTreeMap.Raw α β cmp} [Std.TransCmp cmp]
  [inst : BEq α] [Std.LawfulBEqCmp cmp],
  t.WF → ∀ {l : List ((a : α) × β a)} {k : α}, k ∈ t.insertMany l → (List.map Sigma.fst l).contains k = false → k ∈ t