@SuppressWarnings("unchecked") void removeBox(ValueBox vb){
  if (vb == null)   return;
  if (boxes == vb) {
    boxes=null;
  }
 else   if (boxes instanceof List) {
    List<ValueBox> list=(List<ValueBox>)boxes;
    list.remove(vb);
  }
}

@ SuppressWarnings ( "unchecked" ) void removeBox ( ValueBox vb ) { if ( vb == null ) return ; if ( boxes == vb ) { boxes = null ; } else if ( boxes instanceof List ) { List < ValueBox > list = ( List < ValueBox > ) boxes ; list . remove ( vb ) ; } }
removes a value box from this operand .
