∀ {α : Type u₁} {β : Type u₂} (h : CategoryTheory.Discrete α ≌ CategoryTheory.Discrete β) (a : α),
  (CategoryTheory.Discrete.equivOfEquivalence h) a =
    (CategoryTheory.Discrete.as ∘ h.functor.obj ∘ CategoryTheory.Discrete.mk) a