let configuration = STPPaymentConfiguration()
        configuration.companyName = "XXX"
        configuration.canDeletePaymentOptions = true
        configuration.publishableKey = "pk_live_XXX"
        configuration.appleMerchantIdentifier = "merchant.XXX"
        paymentOptionsViewController = STPPaymentOptionsViewController(configuration: configuration, theme: STPTheme.default(), customerContext: STPCustomerContext(keyProvider: self.customerContext), delegate: self)
        navigationController?.pushViewController(paymentOptionsViewController, animated: true)