def validate_billing_agreement(
      amazon_billing_agreement_id,
      merchant_id: @merchant_id,
      mws_auth_token: nil
    )

      parameters = {
        'Action' => 'ValidateBillingAgreement',
        'SellerId' => merchant_id,
        'AmazonBillingAgreementId' => amazon_billing_agreement_id
      }

      optional = {
        'MWSAuthToken' => mws_auth_token
      }

      operation(parameters, optional)
    end
def validate_billing_agreement(
      amazon_billing_agreement_id,
      merchant_id: @merchant_id,
      mws_auth_token: nil
    )

      parameters = {
        'Action' => 'ValidateBillingAgreement',
        'SellerId' => merchant_id,
        'AmazonBillingAgreementId' => amazon_billing_agreement_id
      }

      optional = {
        'MWSAuthToken' => mws_auth_token
      }

      operation(parameters, optional)
    end
Validates the status of the BillingAgreement object and the payment
 method associated with it
 @see https://pay.amazon.com/documentation/apireference/201751630#201751720
 @param amazon_billing_agreement_id [String]
 @optional merchant_id [String]
 @optional mws_auth_token [String]