∀ {α : Type u_1} {δ : Type u_2} (motive : (Std.DTreeMap.Internal.Impl α fun x => δ) → Sort u_3)
  (h_1 : Unit → motive Std.DTreeMap.Internal.Impl.leaf)
  (h_2 :
    (size : ℕ) →
      (k' : α) →
        (v' : δ) →
          (l r : Std.DTreeMap.Internal.Impl α fun x => δ) → motive (Std.DTreeMap.Internal.Impl.inner size k' v' l r)),
  (match Std.DTreeMap.Internal.Impl.leaf with
    | Std.DTreeMap.Internal.Impl.leaf => h_1 ()
    | Std.DTreeMap.Internal.Impl.inner size k' v' l r => h_2 size k' v' l r) =
    h_1 ()