∀ {V : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} V] {G : Type u_3} [inst_1 : Monoid G]
  {X Y : CategoryTheory.Functor (CategoryTheory.SingleObj G) V} (f : X ⟶ Y) (g : G),
  CategoryTheory.CategoryStruct.comp (X.map g) (f.app PUnit.unit) =
    CategoryTheory.CategoryStruct.comp (f.app PUnit.unit) (Y.map g)