public Operand GetAdditionalOperand(int index)
{
if (addition == null || addition.AdditionalOperands == null)
return null;
Debug.Assert(index >= 3, @"No Index");
//Debug.Assert(index < 255, @"No Index");
SizeAdditionalOperands(index - 3);
return addition.AdditionalOperands[index - 3];
}