proposition: Lemma isaprop_is_nat_trans (C C' : precategory_data) (hs: has_homsets C') (F F' : functor_data C C') (t : nat_trans_data F F'): isaprop (is_nat_trans F F' t).
proof: Proof. repeat (apply impred; intro). apply hs. Qed.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.TransportMorphisms UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Univalence