code: @Override
      public AddInstanceGroupsResult addInstanceGroups(AddInstanceGroupsRequest request) {
          request = beforeClientExecution(request);
          return executeAddInstanceGroups(request);
      }
docs: <p>
  Adds one or more instance groups to a running cluster.
  </p>
  
  @param addInstanceGroupsRequest
  Input to an AddInstanceGroups call.
  @return Result of the AddInstanceGroups operation returned by the service.
  @throws InternalServerErrorException
  Indicates that an error occurred while processing the request and that the request was not completed.
  @sample AmazonElasticMapReduce.AddInstanceGroups
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticmapreduce-2009-03-31/AddInstanceGroups"
  target="_top">AWS API Documentation</a>