code: @Override
      public DescribeRetentionConfigurationsResult describeRetentionConfigurations(DescribeRetentionConfigurationsRequest request) {
          request = beforeClientExecution(request);
          return executeDescribeRetentionConfigurations(request);
      }
docs: <p>
  Returns the details of one or more retention configurations. If the retention configuration name is not
  specified, this action returns the details for all the retention configurations for that account.
  </p>
  <note>
  <p>
  Currently, AWS Config supports only one retention configuration per region in your account.
  </p>
  </note>
  
  @param describeRetentionConfigurationsRequest
  @return Result of the DescribeRetentionConfigurations operation returned by the service.
  @throws InvalidParameterValueException
  One or more of the specified parameters are invalid. Verify that your parameters are valid and try again.
  @throws NoSuchRetentionConfigurationException
  You have specified a retention configuration that does not exist.
  @throws InvalidNextTokenException
  The specified next token is invalid. Specify the <code>nextToken</code> string that was returned in the
  previous response to get the next page of results.
  @sample AmazonConfig.DescribeRetentionConfigurations
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/config-2014-11-12/DescribeRetentionConfigurations"
  target="_top">AWS API Documentation</a>