code: public Map<IssueCategoryModel, Integer> getMigrationEffortBySeverity(GraphRewrite event,
          ProjectModelTraversal traversal, Set<String> includeTags, Set<String> excludeTags, Set<String> issueCategoryIDs, boolean recursive)
      {
          MapSumEffortAccumulatorFunction<IssueCategoryModel> accumulator =  new MapSumEffortAccumulatorFunction<IssueCategoryModel>()
          {
              public IssueCategoryModel vertexToKey(Vertex effortReportVertex)
              {
                  return frame(effortReportVertex).getIssueCategory();
              }
  
              @Override
              public void accumulate(Vertex effortReportVertex)
              {
                  /*
                   * If it is a detail only issue, then summaries should not include it in the count.
                   */
                  if (frame(effortReportVertex).getIssueDisplayMode() == IssueDisplayMode.DETAIL_ONLY)
                      return;
  
                  super.accumulate(effortReportVertex);
              }
          };
          this.getMigrationEffortDetails(traversal, includeTags, excludeTags, issueCategoryIDs, recursive, true, accumulator);
          return accumulator.getResults();
      }
docs: Returns the total incidents in all of the {@link ClassificationModel}s associated with the files in this project by severity.