code: @Override
      public ListSigningCertificatesResult listSigningCertificates(ListSigningCertificatesRequest request) {
          request = beforeClientExecution(request);
          return executeListSigningCertificates(request);
      }
docs: <p>
  Returns information about the signing certificates associated with the specified IAM user. If none exists, the
  operation returns an empty list.
  </p>
  <p>
  Although each user is limited to a small number of signing certificates, you can still paginate the results using
  the <code>MaxItems</code> and <code>Marker</code> parameters.
  </p>
  <p>
  If the <code>UserName</code> field is not specified, the user name is determined implicitly based on the AWS
  access key ID used to sign the request for this API. This operation works for access keys under the AWS account.
  Consequently, you can use this operation to manage AWS account root user credentials even if the AWS account has
  no associated users.
  </p>
  
  @param listSigningCertificatesRequest
  @return Result of the ListSigningCertificates operation returned by the service.
  @throws NoSuchEntityException
  The request was rejected because it referenced a resource entity that does not exist. The error message
  describes the resource.
  @throws ServiceFailureException
  The request processing has failed because of an unknown error, exception or failure.
  @sample AmazonIdentityManagement.ListSigningCertificates
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/iam-2010-05-08/ListSigningCertificates" target="_top">AWS
  API Documentation</a>