Verifies a ticket coupon.
The verifyCoupon() function returns a Promise that resolves to an
VerifyCouponResponse when the ticket coupon
has been updated.
If the coupon has been verified, the VerifyCouponResponse will contain
an invoice property with an invoice that includes the coupon discounts.
If the coupon fails verification, the VerifyCouponResponse will contain
a discountErrors property including information about why the verification
failed.
You may want to call the verifyCoupon() function in an input element's
onCustomValidation() event
handler to validate a coupon code while the form is being filled out.
Note: To work with the Wix Events API, you need to publish your site.
ID of the event that the ticket coupon is for.
ID of the reservation that the ticket coupon is for.
Code of the coupon to verify.