∀ {F : Type u_6} {α : Type u_7} {β : Type u_8} {inst : BiheytingAlgebra α} {inst_1 : BiheytingAlgebra β}
  {inst_2 : FunLike F α β} [self : BiheytingHomClass F α β] (f : F) (a b : α), f (a ⇨ b) = f a ⇨ f b