Photoshop scripting move one group inside of other -

i'm trying move 1 layerset other layerset in photoshop scripting. here's code:

// source var srcgroup = app.activedocument.layersets.add(); srcgroup.name = 'source';  // target var targetgroup = app.activedocument.layersets.add(); targetgroup.name = 'target';  srcgroup.move(targetgroup, elementplacement.inside); 

this gives error "error 1220: illegal argument". if change second argument elementplacement.placeafter, error gone not quite doing want.

as found out not values of elementplacement valid object types. decided make workarround adding dummiegroup , place source before dummy. @ end dummy removed.

var srcgroup = app.activedocument.layersets.add(); srcgroup.name = "source"; var targetgroup = app.activedocument.layersets.add(); targetgroup.name = "target";  //adding dummy inside target layerset var dummiegroup = targetgroup.layersets.add(); dummiegroup.name = "dummy";  srcgroup.move(dummiegroup, elementplacement.placebefore); dummiegroup.remove(); 

to remove layerset have empty.