∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  {S : D} {T : CategoryTheory.Functor C D} {f f' : CategoryTheory.StructuredArrow S T} (g g_1 : f.right ⟶ f'.right)
  (e_g : g = g_1) (w : CategoryTheory.CategoryStruct.comp f.hom (T.map g) = f'.hom),
  CategoryTheory.StructuredArrow.homMk g w = CategoryTheory.StructuredArrow.homMk g_1 ⋯