fact: Definition sub_precategory_predicate_morphisms {C : category} (C':sub_precategories C) (a b : C) : hsubtype (a --> b) := pr2 (pr1 C') a b.
imports: UniMath.Foundations.Sets UniMath.MoreFoundations.PartA UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos