OptionalmethodArgs: {Checks if one or more DiscountGroups exist for the provided query predicate.
Returns a 200 status if any DiscountGroups match the query predicate, or a 404 status otherwise.
OptionalmethodArgs: {Creates a DiscountGroup in the Project. This request generates the DiscountGroupCreated Message.
If the [limit](/../api/limits#discount-groups) for active Discount Groups has been reached, a [MaxDiscountGroupsReached](ctp:api:type:MaxDiscountGroupsReachedError) error is returned.
Retrieves all DiscountGroups in the Project.