∀ (p : ENNReal) (α : Type u_2) (β : Type u_3) (γ : Type u_4) [hp : Fact (1 ≤ p)] [inst : PseudoEMetricSpace α]
  [inst_1 : PseudoEMetricSpace β] [inst_2 : PseudoEMetricSpace γ] (x : WithLp p (WithLp p (α × β) × γ)),
  (IsometryEquiv.withLpProdAssoc p α β γ) x = WithLp.toLp p (x.fst.fst, WithLp.toLp p (x.fst.snd, x.snd))