∀ {α : Type u} {β : Type v} [inst : BEq α] [inst_1 : Hashable α] [EquivBEq α] [LawfulHashable α]
  {m : Std.DHashMap.Internal.Raw₀ α fun x => β} {a : α} {b : β},
  Std.DHashMap.Internal.Raw.WFImp ↑m →
    (Std.DHashMap.Internal.toListModel (↑(Std.DHashMap.Internal.Raw₀.Const.getThenInsertIfNew? m a b).2).buckets).Perm
      (Std.Internal.List.insertEntryIfNew a b (Std.DHashMap.Internal.toListModel (↑m).buckets))