public static IntArrayBag union(IntArrayBag b1, IntArrayBag b2)
   {   
      IntArrayBag answer = new IntArrayBag(b1.getCapacity( ) + b2.getCapacity( ));
      
      System.arraycopy(b1.data, 0, answer.data, 0, b1.manyItems);
      System.arraycopy(b2.data, 0, answer.data, b1.manyItems, b2.manyItems);
      answer.manyItems = b1.manyItems + b2.manyItems;
      
      return answer;
   }