百度echarts图表如何设置主标题和副标题

title: [
 {
  text: "主标题",
  left: '20%', //主标题位置
  top: '40%',
  textStyle: {
   color: "#f00",
   fontSize: 32,
   fontWeight: 'bold'
  }
 },
{
 subtext: "副标题",
 itemGap: 12, //主副标题间距
 left: '20%', //副标题位置
 top: '50%',
 subtextStyle: {
    color: "#000",
    fontSize: 18,
    fontWeight: '500'
  }
 }
],