∀ (C : Type u_2) [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Preadditive C] {X Y Z : C}
  (x : X ⟶ Y) (x_1 : Y ⟶ Z),
  (fun x_2 x_3 => CategoryTheory.CategoryStruct.comp x x_1) =
    CategoryTheory.CategoryStruct.comp (fun x_2 x_3 => x) fun x x_2 => x_1