how to identify document has any timeline animation using Photoshop script?

test this )

function has_timeline()

    {

    try {

        var r = new ActionReference();

        r.putProperty(charIDToTypeID('Prpr'), stringIDToTypeID('documentTimelineSettings'));

        r.putClass(stringIDToTypeID('timeline'));

        try { executeActionGet(r); } catch (e) { return false; }

        return true;

        }

    catch (e) { alert(e); }

    }