pub async fn validate_subscription_discount_code_in_transaction(
transaction: &mut Transaction<'_, Postgres>,
offers: &dyn SubscriptionOfferStore,
billing_scope_id: BillingScopeId,
plan_key: &PlanKey,
code: &SubscriptionDiscountCode,
) -> Result<Option<SubscriptionDiscountCodeQuote>, SubscriptionDiscountOperationError>