@NotNull
  private static List<Line> convertMode(@NotNull List<? extends Line> original, @NotNull ComparisonPolicy policy) {
    List<Line> result = new ArrayList<>(original.size());
    for (Line line : original) {
      Line newLine = line.myPolicy != policy
                     ? new Line(line.getContent(), policy)
                     : line;
      result.add(newLine);
    }
    return result;
  }
@NotNull
  private static List<Line> convertMode(@NotNull List<? extends Line> original, @NotNull ComparisonPolicy policy)