code: public Coupon getCoupon(final String couponCode) {
          if (couponCode == null || couponCode.isEmpty())
              throw new RuntimeException("couponCode cannot be empty!");
  
          return doGET(Coupon.COUPON_RESOURCE + "/" + couponCode, Coupon.class);
      }
docs: Get a Coupon
  <p>
  
  @param couponCode The code for the {@link Coupon}
  @return The {@link Coupon} object as identified by the passed in code