{α : Type u_1} →
  {γ : α → Type u_2} →
    (motive : Std.DTreeMap.Internal.Impl.BalancedTree α γ → Sort u_3) →
      (x : Std.DTreeMap.Internal.Impl.BalancedTree α γ) →
        ((r' : Std.DTreeMap.Internal.Impl α γ) → (hr' : r'.Balanced) → motive { impl := r', balanced_impl := hr' }) →
          motive x