Finding shapes outside prBoundary

I used this code from Cadence on my layout:

procedure(CCSFindShapesOutsidePrBoundary(@optional (cv geGetWindowCellView()))
  let((temp_list prShapeID realShapes (finalShapes nil)(rest nil))
 
    realShapes=cv~>shapes
    prShapeID=dbCreatePolygon(cv leGetEntryLayer() cv~>prBoundary~>points)

    foreach(shape realShapes
temp_list=dbLayerXor(cv leGetEntryLayer() list(shape) list(prShapeID))
if(length(temp_list)==1 then
    mapcar('dbDeleteObject temp_list)
else
    printf("\n shape with bBox %L is outside prBoundary object\n"
    shape~>bBox)
   finalShapes=cons(shape finalShapes)
   mapcar('dbDeleteObject temp_list)
) ;if length
      ) ;foreach shape
   
    foreach(x realShapes if(!member(x finalShapes) then rest=cons(x rest)))
    foreach(x rest
  if(temp_list=dbLayerAnd(cv leGetEntryLayer() list(x) list(prShapeID))
  then     
     mapcar('dbDeleteObject temp_list)
else
printf("\n shape with bBox %L is outside prBoundary object\n"
x~>bBox)
finalShapes=cons(x finalShapes)
    ); if temp_list
);foreach x
   
   dbDeleteObject(prShapeID)
   finalShapes
  ) ;let
) ;procedure

but got the error:

*Error* dbCreatePolygon: Polygon needs at least 3 points - nil

Is there something wrong with this code ?  It seems that cv~>prBoundary~>points return nil.

Please help,

Thanks,

HP