Replaces the whole pool of available coupon codes of a unique-code variant with a new batch. Codes that were already redeemed are left untouched. Requires a producer access token for the application.

The rules match Upload Coupon Codes: up to 5,000 codes of up to 255 characters, a code already on this variant is skipped and counted, and a code used on a different variant in the same store fails the request. The variant must belong to a unique_code product, and the product must not be published.