∀ {B : Type u_2} [inst : CategoryTheory.Bicategory B] {C : Type u_6} [inst_1 : CategoryTheory.Bicategory C]
  {F G : CategoryTheory.OplaxFunctor B C} (η : CategoryTheory.Oplax.OplaxTrans F G) (η' : η.StrongCore) {a b c : B}
  (f : a ⟶ b) (g : b ⟶ c),
  CategoryTheory.CategoryStruct.comp (η'.naturality (CategoryTheory.CategoryStruct.comp f g)).hom
      (CategoryTheory.Bicategory.whiskerLeft (η.app a) (G.mapComp f g)) =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.whiskerRight (F.mapComp f g) (η.app c))
      (CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.associator (F.map f) (F.map g) (η.app c)).hom
        (CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.whiskerLeft (F.map f) (η'.naturality g).hom)
          (CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.associator (F.map f) (η.app b) (G.map g)).inv
            (CategoryTheory.CategoryStruct.comp (CategoryTheory.Bicategory.whiskerRight (η'.naturality f).hom (G.map g))
              (CategoryTheory.Bicategory.associator (η.app a) (G.map f) (G.map g)).hom))))