∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.HasShift C ℤ]
  {A B : CategoryTheory.Pretriangulated.Triangle C} (φ : A ⟶ B) [CategoryTheory.IsIso φ], CategoryTheory.IsIso φ.hom₂