Pass in a payerId and one or more payment methods in order to save those payment methods to that existing payer within ClientPay.
|accessId*||String||Unique identifier that ensures that the integrator has the authorization to make requests on behalf of the customer. (Specifically, a customer's merchant account)|
|token*||Object/Hash||Object containing authentication parameters - most crucially the requestId which is required with every call. For more information, see the Token Object.|
|payerId*||String||ID of the payer for whom you are adding a payment method.|
|paymentMethods*||Array of Objects||Array of Payment Method Objects|