code: @Override
      public ListInstanceGroupsResult listInstanceGroups(ListInstanceGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeListInstanceGroups(request);
      }
docs: <p>
  Provides all available details about the instance groups in a cluster.
  </p>
  
  @param listInstanceGroupsRequest
  This input determines which instance groups to retrieve.
  @return Result of the ListInstanceGroups operation returned by the service.
  @throws InternalServerException
  This exception occurs when there is an internal failure in the EMR service.
  @throws InvalidRequestException
  This exception occurs when there is something wrong with user input.
  @sample AmazonElasticMapReduce.ListInstanceGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticmapreduce-2009-03-31/ListInstanceGroups"
  target="_top">AWS API Documentation</a>