code: public List<Change> asRemovedChanges() {
          final WeeklyOpeningHours normalized = this.normalize();
          final List<Change> changes = new ArrayList<>();
          for (final DayOpeningHours doh : normalized) {
              changes.addAll(doh.asRemovedChanges());
          }
          return changes;
      }
docs: Returns all days and hour ranges as if they were removed.
  
  @return Removed day changes.