∀ {C : Type u_2} [inst : CategoryTheory.Bicategory C] (X : C) (X_1 Y : X ⟶ X),
  CategoryTheory.CategoryStruct.comp
      (CategoryTheory.Bicategory.associator X_1 (CategoryTheory.CategoryStruct.id X) Y).hom
      (CategoryTheory.Bicategory.whiskerLeft X_1 (CategoryTheory.Bicategory.leftUnitor Y).hom) =
    CategoryTheory.Bicategory.whiskerRight (CategoryTheory.Bicategory.rightUnitor X_1).hom Y