code: @Override
      public ListKeysResult listKeys(ListKeysRequest request) {
          request = beforeClientExecution(request);
          return executeListKeys(request);
      }
docs: <p>
  Gets a list of all customer master keys (CMKs) in the caller's AWS account and region.
  </p>
  
  @param listKeysRequest
  @return Result of the ListKeys operation returned by the service.
  @throws DependencyTimeoutException
  The system timed out while trying to fulfill the request. The request can be retried.
  @throws KMSInternalException
  The request was rejected because an internal exception occurred. The request can be retried.
  @throws InvalidMarkerException
  The request was rejected because the marker that specifies where pagination should next begin is not
  valid.
  @sample AWSKMS.ListKeys
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/kms-2014-11-01/ListKeys" target="_top">AWS API
  Documentation</a>