[Closed] instance postion controller

Hi, hopefully this is a real easy one. How can i instance the position controller of one object to another. I know how to do it by hand, but not with script.

$[1].pos.controller = copy $[2].pos.controller --this works but isn't a instance.
 $[1].pos.controller = instance $[2].pos.controller -- this throws an error
 

thanks, David