/// <summary>
/// Stores the credit card information at the provider and generates a tokenNumber.
/// </summary>
/// <param name="creditCard"></param>
/// <param name="expirationDate"></param>
/// <returns></returns>
public async Task <IEnumerable <AccountSummary> > RetrieveBillingAccountsByPolicyId(int policyId)
{
return(await BillingAccountManager.RetrieveBillingAccountsForPolicyId(policyId));
}