∀ {B : Type u₁} [inst : CategoryTheory.Bicategory B] {C : Type u₂} [inst_1 : CategoryTheory.Bicategory C]
  {G H : CategoryTheory.Pseudofunctor B C} (θ : G ⟶ H) {a b : B} {a' : C} (f : a' ⟶ G.obj a) {g h : a ⟶ b} (β : g ⟶ h),
  CategoryTheory.CategoryStruct.comp
      (CategoryTheory.Bicategory.whiskerLeft f (CategoryTheory.Bicategory.whiskerRight (G.map₂ β) (θ.app b)))
      (CategoryTheory.Bicategory.whiskerLeft f (θ.naturality h).hom) =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.whiskerLeft f (θ.naturality g).hom)
      (CategoryTheory.Bicategory.whiskerLeft f (CategoryTheory.Bicategory.whiskerLeft (θ.app a) (H.map₂ β)))