Error when enableLocationEvents

Hi, 

When i enable Location Events e get the Error: Invalid

'$.Toybox.Lang.Method(info as Any) as Any' passed as parameter 2 of type '$.Toybox.Lang.Method(loc as $.Toybox.Position.Info) as Void'

Code:

// onStart() is called on application start up
    function onStart(state) {
        System.println("WinsurfApp - onStart start");
          var options = {
            :acquisitionType => Position.LOCATION_CONTINUOUS};
        Position.enableLocationEvents(options, method(:onPosition));

        System.println("WinsurfApp - onStart end");
    }

    function onPosition(info)
    {
        System.println("WinsurfApp - event onPosition");
        _posnInfo = info;
        _currentView.onPosition(info);
        WatchUi.requestUpdate();
    }
What can i do?