{B : Type u₁} →
  [inst : CategoryTheory.Bicategory B] →
    {C : Type u₂} →
      [inst_1 : CategoryTheory.Bicategory C] →
        {F G : CategoryTheory.Pseudofunctor B C} →
          (η : F ⟶ G) → CategoryTheory.CategoryStruct.comp (CategoryTheory.CategoryStruct.id F) η ≅ η