proposition: Lemma vcomp_lunitor_CAT {C D : category} {F G : [C, D]} (α : [C, D]⟦F, G⟧) : lwhisker_CAT (id1_CAT C) α · lunitor_CAT G = lunitor_CAT F · α.
proof: Proof. apply (nat_trans_eq D); intro c. rewrite id_left; apply id_right. Qed.
imports: UniMath.Foundations.PartD UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.FunctorCategory UniMath.CategoryTheory.whiskering