如何使用amcharts 4在地图中的多个饼图中创建共享图例？

// 引入amCharts库的JavaScript文件和CSS文件
<script src="amcharts4/core.js"></script>
<script src="amcharts4/maps.js"></script>
<script src="amcharts4/charts.js"></script>
<link rel="stylesheet" href="amcharts4/core.css">
<link rel="stylesheet" href="amcharts4/maps.css">
<link rel="stylesheet" href="amcharts4/charts.css">

// 创建一个包含所有饼图的父容器
<div id="chartContainer"></div>

// 初始化amCharts库，创建一个地图对象
var chart = am4core.create("chartContainer", am4maps.MapChart);

// 设置地图的属性和配置
chart.projection = new am4maps.projections.Miller();
chart.background.fill = am4core.color("#ffffff");

// 创建每个饼图对象
var pie1 = chart.series.push(new am4charts.PieSeries());
var pie2 = chart.series.push(new am4charts.PieSeries());

// 设置饼图的属性和配置
pie1.dataFields.value = "value1";
pie1.dataFields.category = "category1";
pie1.legendSettings.labelText = "[bold {color}]{name}";
pie1.colors.list = [
  am4core.color("#336699"),
  am4core.color("#669933"),
  am4core.color("#993366")
];

pie2.dataFields.value = "value2";
pie2.dataFields.category = "category2";
pie2.legendSettings.labelText = "[bold {color}]{name}";
pie2.colors.list = [
  am4core.color("#cc6666"),
  am4core.color("#66cc66"),
  am4core.color("#6666cc")
];

// 创建共享的图例容器
var legendContainer = am4core.create("legendContainer", am4core.Container);
legendContainer.layout = "vertical";
chart.legend = legendContainer;

// 将每个饼图对象的图例容器ID设置为共享的图例容器ID
pie1.legend.parent = legendContainer;
pie2.legend.parent = legendContainer;

// 设置数据源并渲染图表
chart.data = [{
  "category1": "Category 1",
  "value1": 100,
  "category2": "Category 1",
  "value2": 200
}, {
  "category1": "Category 2",
  "value1": 150,
  "category2": "Category 2",
  "value2": 250
}, {
  "category1": "Category 3",
  "value1": 200,
  "category2": "Category 3",
  "value2": 300
}];