docs: public void setInto(ReadWritablePeriod period, Object object, Chronology chrono) {
          String str = (String) object;
          PeriodFormatter parser = ISOPeriodFormat.standard();
          period.clear();
          int pos = parser.parseInto(period, str, 0);
          if (pos < str.length()) {
              if (pos < 0) {
                  // Parse again to get a better exception thrown.
                  parser.withParseType(period.getPeriodType()).parseMutablePeriod(str);
              }
              throw new IllegalArgumentException("Invalid format: \"" + str + '"');
          }
      }