fact: Definition isaset_pb_2cell {p q : pb_cone} (φ ψ : pb_1cell p q) : isaset (pb_2cell φ ψ).
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.Bicategories.Core.Bicat UniMath.Bicategories.Core.Invertible_2cells UniMath.Bicategories.Core.Univalence