cartesianchart using actionscript(cartesian chart)

Question

this function will create the colum chart...

private function columnChart():void {

    var columnChart:ColumnChart = new ColumnChart();
    columnChart.dataProvider = getDataProvider();
    columnChart.percentWidth = 100;
    columnChart.percentHeight = 100;


columnChart.showDataTips = true;
var catAxis:CategoryAxis = new CategoryAxis();
catAxis.categoryField = "Name";
columnChart.horizontalAxis = catAxis;  


var col:ColumnSeries = new ColumnSeries();
col.yField = "TotalRevenue"; 
col.displayName="TotalRevenue";

var col1:ColumnSeries = new ColumnSeries();
col1.yField = "TotalCost";
col1.displayName="TotalCost";

var col2:ColumnSeries = new ColumnSeries();
col2.yField = "Margin";
col2.displayName="Margin";



columnChart.series=[col,col1,col2];
    // add a lengend
var legendAnnualBen:Legend = new Legend();
legendAnnualBen.dataProvider = columnChart;
bx2.removeAllChildren();  
bx2.addChild(columnChart);
bx2.addChild(legendAnnualBen);
}

now i need to add line series to this chart using action script how to add then 2nd ry Axis and series