fact: Definition comp_pb_2cell {p q : pb_cone} {φ ψ χ : pb_1cell p q} (η₁ : pb_2cell φ ψ) (η₂ : pb_2cell ψ χ) : pb_2cell φ χ.
imports: UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.Bicategories.Core.Bicat UniMath.Bicategories.Core.Invertible_2cells UniMath.Bicategories.Core.Univalence