docs: int getWeeksInYear(int year) {
          long firstWeekMillis1 = getFirstWeekOfYearMillis(year);
          long firstWeekMillis2 = getFirstWeekOfYearMillis(year + 1);
          return (int) ((firstWeekMillis2 - firstWeekMillis1) / DateTimeConstants.MILLIS_PER_WEEK);
      }