∀ {α : Type u} {β : α → Type v} {m : Std.DHashMap.Raw α β} [inst : BEq α] [inst_1 : Hashable α] [inst_2 : LawfulBEq α],
  m.WF →
    ∀ {l : List ((a : α) × β a)} {k k' : α} (k_beq : (k == k') = true) {v : β k},
      List.Pairwise (fun a b => (a.fst == b.fst) = false) l → ⟨k, v⟩ ∈ l → (m.insertMany l).get? k' = some (cast ⋯ v)