如何在amcharts的更新图表中添加amgraph

Question

我想在阶梯线图表中显示多个折线图。但是问题是    对于一个响应，我只需要显示一个折线图，对于    我需要显示2条线图的另一种回应。

     this.timeChart = this.AmCharts.makeChart("chartdiv2", {
  "type": "serial",
  "theme": "light",
  "marginRight": 80,
  "autoMarginOffset": 20,
  "marginTop": 7,
  "dataProvider": chartData,
"valueAxes": [{
    "axisAlpha": 0,
    "position": "left",
    "title": "Response Count",
    "autoGridCount": false,
    "gridCount": 5,
    "gridAlpha": 0
}],
"graphs": [{
    "id": "g1",
    "balloonText": "[[title]]<br>[[category]]<br><b>[[value]] </b>",
    "lineThickness": 1,
    "bullet": "square",
    "type": "step",
    "bulletAlpha": 0,
    "bulletSize": 4,
    "bulletBorderAlpha": 0,
    "valueField": "members",
    'lineColor': 'pink',
    'title': 'Member Response',
},

此后，我想在更新图表中添加另一个图形对象。 怎么做。