∀ {B : Type u} [inst : CategoryTheory.Bicategory B] {F : CategoryTheory.Pseudofunctor B CategoryTheory.Cat}
  (P : F.ObjectProperty) [inst_1 : P.IsClosedUnderMapObj] (X : B),
  P.fullsubcategory.mapId X = CategoryTheory.Cat.Hom.isoMk (P.mapId X)