∀ {α : Type u} [inst : BEq α] [inst_1 : Hashable α] {β : Type v} {m : Std.DHashMap.Raw α fun x => β} [EquivBEq α]
  [LawfulHashable α],
  m.WF →
    ∀ {l : List (α × β)} {k k' : α},
      (k == k') = true →
        List.Pairwise (fun a b => (a.1 == b.1) = false) l →
          k ∈ List.map Prod.fst l →
            ∀ {h' : k' ∈ Std.DHashMap.Raw.Const.insertMany m l},
              (Std.DHashMap.Raw.Const.insertMany m l).getKey k' h' = k