问Swift:链接多个网络请求，Alamofire

EN

let dispatchQueue = DispatchQueue.global(qos: .background)
        dispatchQueue.async {
        if MDUtilites.isMediaPresent() {
                let _ = self.fetchMediaList()
                self.semaphore.wait()
                
            }
}

func fetchMediaList() {
    MDApiManager.sharedInstance.fetchMediaList { (dict, status) in
        switch (status) {
        case .failed(let code, _, let description):
            print("failed:")
            print(code)
            print(description)
            self.semaphore.signal()
        case .success(_, _ , _):
            print("success")
            
            if let data = dict,
                let list = data.parseWith(type: MediaBase.self)?.list {
                self.newMedia = list
                NotificationCenter.default.post(name: Notification.Name(rawValue: MEDIA_UPDATE), object: nil)
                //                    self.mediaListSections = list
                //                    self.getCategories(data: list)
            }
            self.semaphore.signal()
        case .unknown:
            print("DEBUG: unknown fetchMediaList")
            self.fetchMediaList()
        //                self.semaphore.signal()
        case .error(let aError):
            print(aError)
            self.semaphore.signal()
        }
    }
}