@NotNull
  private static List<String> getDiffContentTitles(@NotNull TextMergeRequest mergeRequest) {
    List<String> titles = MergeUtil.notNullizeContentTitles(mergeRequest.getContentTitles());
    titles.set(ThreeSide.BASE.getIndex(), DiffBundle.message("merge.version.title.merged.result"));
    return titles;
  }
@NotNull
  private static List<String> getDiffContentTitles(@NotNull TextMergeRequest mergeRequest)