     var created: Date? { get }
     var currentPeriodEnd: Date? { get }
     var currentPeriodStart: Date? { get }
-    var customerId: String? { get }
+    var customer: String? { get }
     var daysUntilDue: Int? { get }
     var discount: D? { get }
     var endedAt: Date? { get }

    public var created: Date?
    public var currentPeriodEnd: Date?
    public var currentPeriodStart: Date?
    public var customerId: String?
    public var daysUntilDue: Int?
    public var discount: StripeDiscount?
    public var endedAt: Date?

        case created
        case currentPeriodEnd = "current_period_end"
        case currentPeriodStart = "current_period_start"
        case customer
        case daysUntilDue = "days_until_due"
        case discount
        case endedAt = "ended_at"
