∀ {B : Type u_1} [inst : CategoryTheory.Bicategory B] [inst_1 : CategoryTheory.Bicategory.Strict B]
  (F : CategoryTheory.Pseudofunctor B CategoryTheory.Cat) {b₀ b₁ : B} (f : b₀ ⟶ b₁) (X : ↑(F.obj b₀)) {Z : ↑(F.obj b₁)}
  (h : (F.map (CategoryTheory.CategoryStruct.id b₁)).toFunctor.obj ((F.map f).toFunctor.obj X) ⟶ Z),
  CategoryTheory.CategoryStruct.comp ((F.mapComp' f (CategoryTheory.CategoryStruct.id b₁) f ⋯).hom.toNatTrans.app X) h =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.eqToHom ⋯)
      (CategoryTheory.CategoryStruct.comp ((F.mapId b₁).inv.toNatTrans.app ((F.map f).toFunctor.obj X)) h)