What is "myid" in ZingChart docs?

I must be missing something simple, but...: In the ZingChart docs for the API methods, the functions all reference myid, but I can't figure out what is a ZingChart's id. For example, method getseriesvalues:

zingchart.exec('myid', 'getseriesvalues', {});

What does 'myid' refer to in this example code?

Here is my simple ZingChart example code:

 $(function(){
    var myChart = {
        type : "line",
        title : {text: "Hello ZingChart World!"},
        series : [
            {values:[5, 10, 15, 5, 10, 5]},
            {values:[2, 4, 6, 8, 10, 12]}
        ]
    };

    zingchart.render({
        id : "myChartDiv",
        height : 450,
        width : 600,
        data : myChart
    }); 
})

Now let's say I would want to invoke the getseriesvalues method on this chart - what would myid be? myChart? myChartDiv? Neither of them work...