if opt.IsDefined() {
		return fn(opt.Get())
	}
	return None[U]()
}

type ApplicativeFunctor1[H Header[HT], HT, A, R any] struct {
	h  Option[H]
	fn Option[Func1[A, R]]
}

func (r ApplicativeFunctor1[H, HT, A, R]) ApOption(a Option[A]) Option[R] {
	return Ap(r.fn, a)
}

func (r ApplicativeFunctor1[H, HT, A, R]) Ap(a A) Option[R] {
	return r.ApOption(Some(a))
}