if (year in 70..99) year += 1900
      if (year in 0..69) year += 2000

      // If any partial is omitted or out of range, return -1. The date is impossible. Note that leap
      // seconds are not supported by this syntax.
      require(year >= 1601)
      require(month != -1)
      require(dayOfMonth in 1..31)
      require(hour in 0..23)
      require(minute in 0..59)