nl_tokens: there are no properties on a RemoveObserver every object that went as ref through this function can be used as this in any of the RemoveObserver methods
pl_tokens: function RemoveObserver_init ( ref , node ) { let self = Self . get ( node ) ; if ( ! <mask> ) { self = new RemoveObserverPrivate ( node ) ; Self . set ( node , self ) ; } Self . set ( ref , self ) ; }