∀ {C : Type u_1} {D : Type u_2} {E : Type u_3} [inst : CategoryTheory.Category.{v_1, u_1} C]
  [inst_1 : CategoryTheory.Category.{v_2, u_2} D] [inst_2 : CategoryTheory.Category.{v_3, u_3} E] {A : Type u_5}
  [inst_3 : AddMonoid A] [inst_4 : CategoryTheory.HasShift D A] [inst_5 : CategoryTheory.HasShift E A]
  (F : CategoryTheory.SingleFunctors C D A) (G : CategoryTheory.Functor D E) [inst_6 : G.CommShift A] (a : A),
  (F.postcomp G).functor a = (F.functor a).comp G