∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] {X Y : C} (h : CategoryTheory.Retract X Y) {Z : C}
  (h' : CategoryTheory.Retract Y Z),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.CategoryStruct.comp h.i h'.i)
      (CategoryTheory.CategoryStruct.comp h'.r h.r) =
    CategoryTheory.CategoryStruct.id X