import { PaymentMethod } from "@stripe/stripe-js";
import { StripeExtension } from "./index.js";
/**
 * Add payment method to customer.
 *
 * @param paymentMethodId - payment method id (see: https://stripe.com/docs/api/customers/object#payment_method_object-id)
 * @param customerId - customer id (see: https://stripe.com/docs/api/customers/object#customer_object-id)
 * @param ephemeralKey - customer ephemeral key
 * @returns
 */
export declare const addPaymentMethodToCustomer: (this: StripeExtension, paymentMethodId: string, customerId: string, ephemeralKey: string) => Promise<PaymentMethod | undefined>;