∀ {B : Type u₁} [inst : CategoryTheory.Bicategory B] {C : Type u₂} [inst_1 : CategoryTheory.Bicategory C]
  (F : CategoryTheory.LaxFunctor B C) (a : B),
  (CategoryTheory.CategoryStruct.id F).app a = (CategoryTheory.Lax.LaxTrans.id F).app a