code: public static Seconds ofHours(int hours) {
          if (hours == 0) {
              return ZERO;
          }
          return new Seconds(Math.multiplyExact(hours, SECONDS_PER_HOUR));
      }
docs: Obtains a {@code Seconds} representing the number of seconds
  equivalent to a number of hours.
  <p>
  The resulting amount will be second-based, with the number of seconds
  equal to the number of hours multiplied by 3600.
  
  @param hours  the number of hours, positive or negative
  @return the amount with the input hours converted to seconds, not null
  @throws ArithmeticException if numeric overflow occurs