docs: public static YearMonthDay fromCalendarFields(Calendar calendar) {
          if (calendar == null) {
              throw new IllegalArgumentException("The calendar must not be null");
          }
          return new YearMonthDay(
              calendar.get(Calendar.YEAR),
              calendar.get(Calendar.MONTH) + 1,
              calendar.get(Calendar.DAY_OF_MONTH)
          );
      }