code: func (sh *ChiSquareSignificanceHeuristic) IncludeNegatives(includeNegatives bool) *ChiSquareSignificanceHeuristic {
  	sh.includeNegatives = &includeNegatives
  	return sh
  }
docs: // IncludeNegatives indicates whether to filter out the terms that appear
  // much less in the subset than in the background without the subset.