func setupAPI() {
        // using raw string

        do {
            let jsonDecoder = try JSONDecoder().decode([PDF].self, from: self.RawJSON.data(using: .utf8)!)
            self.PDFs = jsonDecoder
            DispatchQueue.main.async {
                self.pdftableView.reloadData()
            }
        } catch {
            print(error)
        }
        // if you want to use URL
        let semaphore = DispatchSemaphore(value: 0)
        let request = URLRequest(url: URL(string: "url")!, timeoutInterval: Double.infinity)

        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data else {
                print(String(describing: error))
                semaphore.signal()
                return
            }
            do {
                let jsonDecoder = try JSONDecoder().decode([PDF].self, from: data)
                self.PDFs = jsonDecoder
                DispatchQueue.main.async {
                    semaphore.signal()
                    self.pdftableView.reloadData()
                }
            } catch {
                print(error)
            }
            semaphore.signal()
        }

        task.resume()
        semaphore.wait()
    }