∀ {A : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} A] {A' : Type u_2}
  [inst_1 : CategoryTheory.Category.{v_2, u_2} A'] {B : Type u} [inst_2 : CategoryTheory.Category.{v, u} B]
  (X : CategoryTheory.Functor (A ⊕ A') B),
  (CategoryTheory.Sum.Swap.equivalenceFunctorEquivFunctorIso.inv.app X).2 =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.Functor.whiskerRight (CategoryTheory.Sum.swapCompInr A' A).inv X)
      ((CategoryTheory.Sum.inr_ A' A).associator (CategoryTheory.Sum.swap A' A) X).hom