proposition: Lemma is_precategory_precgraph : is_precategory precgraph_precategory_data.
proof: Proof. apply is_precategory_one_assoc_to_two. apply make_dirprod. repeat apply make_dirprod; cbn. - exact @cgraph_mor_id_left. - exact @cgraph_mor_id_right. - apply @cgraph_mor_comp_assoc. Qed.
imports: UniMath.Foundations.PartA UniMath.Foundations.Sets UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Categories.HSET.Core UniMath.Combinatorics.CGraph