fact: Definition isaprop_invertible_data {C : category} {tu : tensor_unit C} {ua : unitors_associator tu} : isaprop (unitors_associator_are_z_isos ua).
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.Core.Isos