code: public Coupon delete(RequestOptions options) throws StripeException {
      return delete((Map<String, Object>) null, options);
    }
docs: You can delete coupons via the <a href="https://dashboard.stripe.com/coupons">coupon
  management</a> page of the Stripe dashboard. However, deleting a coupon does not affect any
  customers who have already applied the coupon; it means that new customers can’t redeem the
  coupon. You can also delete coupons via the API.