DiscountCode union
A code discount.
Possible types
[DiscountCodeBasic](https://shopify.dev/docs/admin-api/graphql/reference/discounts-and-marketing/discountcodebasic)
[DiscountCodeBxgy](https://shopify.dev/docs/admin-api/graphql/reference/discounts-and-marketing/discountcodebxgy)
[DiscountCodeFreeShipping](https://shopify.dev/docs/admin-api/graphql/reference/discounts-and-marketing/discountcodefreeshipping)