fact: Definition bifunctor_assoc {B C:category} : [B, [C^op,HSET]] ⟶ [[B,C]^op,HSET].
imports: UniMath.Foundations.Preamble UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.RepresentableFunctors.Precategories UniMath.MoreFoundations.Tactics UniMath.CategoryTheory.opp_precat UniMath.CategoryTheory.yoneda UniMath.CategoryTheory.Categories.HSET.Core