docs: public static int fixedFromGregorian(int year, int month, int day) {
          int yearM1 = year - 1;
          return 365 * yearM1 +
                  yearM1 / 4 -
                  yearM1 / 100 +
                  yearM1 / 400 +
                  (367 * month - 362) / 12 +
                  (month <= 2 ? 0 :
                          isLeapYear(year) ? -1 :
                                  -2) +
                  day;
      }