我是swift的新手。我创建了简单的playground并将扩展名为json的文件添加到playground中。我尝试使用for循环解码结果并打印ID，但是，我收到以下错误..For-in循环要求“People.Type "符合”Sequence“
这是我的json文件。

{
    "id": "1",
    "options": [{
            "id": "11",
            "options": [{
                "id": "111",
                "options": []
            }]
        },
        {
            "id": "2",
            "options": [{
                    "id": "21",
                    "options": []
                },
                {
                    "id": "22",
                    "options": [{
                        "id": "221",
                        "options": []
                    }]
                }
            ]
        }
    ]
}

这里是代码..我试过..

struct People: Codable {
    let id: String
    let options: [People]
}
func loadJson(filename fileName: String) -> People? {
    if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
        do {
            let data = try Data(contentsOf: url)
            let decoder = JSONDecoder()
            let jsonData = try decoder.decode(People.self, from: data)

            print("// Printing the ID of the Decode Json")

            for jsondata in jsonData {

                print("ID: \(jsonData.id)")
            }
            return jsonData
        } catch {
            print("error:\(error)")
        }
    }
    return nil
}
loadJson(filename: "people1")

下面是错误的屏幕截图。