public override bool isOnOrAfter(SerialDate other)
 {
   return this.serial >= other.toSerial();
 }
 public override bool isOnOrBefore(SerialDate other)
 {
   return this.serial <= other.toSerial();
 }
 public override bool isInRange(SerialDate d1, SerialDate d2, int include)
 {
   int num1 = d1.toSerial();
   int num2 = d2.toSerial();
   int num3 = Math.min(num1, num2);
   int num4 = Math.max(num1, num2);
   int num5 = this.toSerial();
   if (include == 3)
     return num5 >= num3 && num5 <= num4;
   else if (include == 1)
     return num5 >= num3 && num5 < num4;
   else if (include == 2)
     return num5 > num3 && num5 <= num4;
   else
     return num5 > num3 && num5 < num4;
 }
 public override bool isOn(SerialDate other)
 {
   return this.serial == other.toSerial();
 }
 public override int compare(SerialDate other)
 {
   return this.serial - other.toSerial();
 }