请给出十个最适合9月去的旅游城市，每个城市推荐一个经典景点，要求以JSON格式输出。
user
```json
{
  "cities": [
    {
      "name": "北京",
      "attraction": "故宫"
    },
    {
      "name": "上海",
      "attraction": "外滩"
    },
    {
      "name": "杭州",
      "attraction": "西湖"
    },
    {
      "name": "西安",
      "attraction": "兵马俑"
    },
    {
      "name": "成都",
      "attraction": "宽窄巷子"
    },
    {
      "name": "桂林",
      "attraction": "漓江"
    },
    {
      "name": "青岛",
      "attraction": "八大关"
    },
    {
      "name": "厦门",
      "attraction": "鼓浪屿"
    },
    {
      "name": "丽江",
      "attraction": "古城"
    },
    {
      "name": "苏州",
      "attraction": "拙政园"
    }
  ]
}
```
assistant