Nothing is displayed

programming flash
1 

var a1:Array = new Array(2,1,3,0);
var a2:Array = new Array(0,2,3);



function aNotInB( avArrayA :Array,
      avArrayB :Array ):Array {
    var lvArray:Array = [];

    for each (var avObjectA:Object in avArrayA) {
        if ( avArrayB.indexOf( avObjectA ) == - 1 ) {
            lvArray.push( avObjectA );
        }
    }// for each

    return lvArray;




}// aNotI


aNotInB(a1, a2);
//trace("lvArray" =lvArray);

What am I doing wrong here?

Thanks
Ian