∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] {D : Type u'} [inst_1 : CategoryTheory.Category.{v', u'} D]
  {W : CategoryTheory.MorphismProperty C} {F₁ F₂ F₃ : W.FunctorsInverting D} (f : F₁ ⟶ F₂) (g : F₂ ⟶ F₃)
  {Z : CategoryTheory.Functor C D} (h : F₃.obj ⟶ Z),
  CategoryTheory.CategoryStruct.comp (CategoryTheory.CategoryStruct.comp f g).hom h =
    CategoryTheory.CategoryStruct.comp f.hom (CategoryTheory.CategoryStruct.comp g.hom h)