∀ (C : Type u_1) (D : Type u_2) [inst : CategoryTheory.Category.{v_1, u_1} C]
  [inst_1 : CategoryTheory.MonoidalCategory C] [inst_2 : CategoryTheory.Category.{v_2, u_2} D]
  [inst_3 : CategoryTheory.MonoidalCategory.MonoidalRightAction Cᵒᵖ Dᵒᵖ] (d : Dᵒᵖ) (c c' : Cᵒᵖ),
  CategoryTheory.MonoidalCategory.MonoidalRightActionStruct.actionAssocIso (Opposite.unop d) (Opposite.unop c)
      (Opposite.unop c') =
    (CategoryTheory.MonoidalCategory.MonoidalRightActionStruct.actionAssocIso d c c').symm.unop