fact: Definition morph_class (C : category) := ∏ (x y : C), hsubtype (x --> y).
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Monics UniMath.CategoryTheory.Epis UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos