∀ {C : Type u_1} (D : Type u_2) [inst : CategoryTheory.Category.{v_1, u_1} C]
  [inst_1 : CategoryTheory.Category.{v_2, u_2} D] [inst_2 : CategoryTheory.MonoidalCategory C]
  [inst_3 : CategoryTheory.MonoidalCategory.MonoidalLeftAction C D] (c : C) (y : D),
  (CategoryTheory.MonoidalCategory.MonoidalLeftAction.actionLeft D c).obj y =
    CategoryTheory.MonoidalCategory.MonoidalLeftActionStruct.actionObj c y