proposition: Lemma identity_of_helper : (fun x : Functor C D => 1 o x o 1) = idmap.
proof: Proof. apply path_forall; intro x. apply identity_of_helper_helper. Defined.
imports: Category.Core Functor.Core Functor.Pointwise.Core NaturalTransformation.Core NaturalTransformation.Paths Functor.Composition.Core Functor.Identity Functor.Paths PathGroupoids Types.Forall HoTT.Tactics Basics.Tactics