docs: public PeriodFormatter toFormatter() {
          PeriodFormatter formatter = toFormatter(iElementPairs, iNotPrinter, iNotParser);
          for (FieldFormatter fieldFormatter : iFieldFormatters) {
              if (fieldFormatter != null) {
                  fieldFormatter.finish(iFieldFormatters);
              }
          }
          iFieldFormatters = (FieldFormatter[]) iFieldFormatters.clone();
          return formatter;
      }