code: public WeeklyOpeningHours normalize() {
  
          final List<DayOpeningHours> days = new ArrayList<>();
  
          for (final DayOpeningHours doh : weeklyOpeningHours) {
              final List<DayOpeningHours> normalized = doh.normalize();
              for (final DayOpeningHours normalizedDay : normalized) {
                  final int idx = days.indexOf(normalizedDay);
                  if (idx < 0) {
                      days.add(normalizedDay);
                  } else {
                      final DayOpeningHours found = days.get(idx);
                      final DayOpeningHours replacement = found.add(normalizedDay);
                      days.set(idx, replacement);
                  }
              }
          }
  
          Collections.sort(days);
  
          return new WeeklyOpeningHours(days.toArray(new DayOpeningHours[days.size()]));
  
      }
docs: Removes all opening hours that span more than one day and puts them as an extra range into the other day. Example: 'Fri
  18:00-03:00,Sat 09:00-18:00' will be converted to 'Fri 18:00-24:00,Sat 00:00-03:00+09:00-18:00'.
  
  @return Weekly opening hours with all opening hours inside the day.