docs: public static PeriodFormatter standard() {
          if (cStandard == null) {
              cStandard = new PeriodFormatterBuilder()
                  .appendLiteral("P")
                  .appendYears()
                  .appendSuffix("Y")
                  .appendMonths()
                  .appendSuffix("M")
                  .appendWeeks()
                  .appendSuffix("W")
                  .appendDays()
                  .appendSuffix("D")
                  .appendSeparatorIfFieldsAfter("T")
                  .appendHours()
                  .appendSuffix("H")
                  .appendMinutes()
                  .appendSuffix("M")
                  .appendSecondsWithOptionalMillis()
                  .appendSuffix("S")
                  .toFormatter();
          }
          return cStandard;
      }