private void add(NullAnalysisResult duplicate) {
      for (int i = 0; i < groupedByValue.size(); i++) {
        Collection<PsiElement> elements = groupedByValue.get(i);
        Collection<PsiElement> other = duplicate.groupedByValue.get(i);
        elements.addAll(other);
      }
    }
private void add(NullAnalysisResult duplicate)