json - 无法将类型“”的值转换为“”

Question

我正在尝试从我创建的 API 中提取数据。在我开始解析/解码数据之前，一切似乎都很顺利。

这些是出现的错误：

这是我的代码

import Foundation
struct VaccineManager {
    
    let vaccineURL = "https://coronavirus.data.gov.uk/api/v1/data?filters=areaType=overview&structure=%7B%22areaType%22:%22areaType%22,%22areaName%22:%22areaName%22,%22areaCode%22:%22areaCode%22,%22date%22:%22date%22,%22newPeopleVaccinatedFirstDoseByPublishDate%22:%22newPeopleVaccinatedFirstDoseByPublishDate%22,%22newPeopleVaccinatedSecondDoseByPublishDate%22:%22newPeopleVaccinatedSecondDoseByPublishDate%22,%22cumPeopleVaccinatedFirstDoseByPublishDate%22:%22cumPeopleVaccinatedFirstDoseByPublishDate%22,%22cumPeopleVaccinatedSecondDoseByPublishDate%22:%22cumPeopleVaccinatedSecondDoseByPublishDate%22%7D&format=json"
    
    func performRequest(vaccineURL: String){
        if let url = URL(string: vaccineURL) {
            let session = URLSession(configuration: .default)
            let task = session.dataTask(with: url) { (data, response, error) in
                if error != nil {
                    print(error!)
                    return
                }
                
                if let safeData = data {
                    parseJASON(vaccineData: safeData)
                    
                }
            }
            task.resume()
            
            
        }
    }
    
    func parseJASON(vaccineData: Data) {
        let decoder = JSONDecoder()
        do{
       let decodedData =  try decoder.decode(VaccineData.self, from: vaccineData)
            print(decodedData.data[0].date)
        } catch {
            print(error)
        }
    }

万一这与它有关，我也有一个包含此代码的文件

struct VaccineData: Decodable {
    let data: Data
}

struct Data: Decodable {
    let newPeopleVaccinatedFirstDoseByPublishDate: Int
}

卡了好几天了，谢谢你的帮助！