如何设置顶级元素以显示下载进度？

Question

所以我想发送多个get请求并让tkinter标签显示进度，但是我注意到顶层仅在所有请求完成后才显示。

我该如何解决？

import tkinter as tk
import requests

window = tk.Tk()

def download():
    global window
    top = tk.Toplevel(window)
    progress_text = tk.StringVar()

    tk.Label(top, textvariable=progress_text, font=('Arial', 12))


    url_list = [' http://www.yahoo.com', ' http://www.google.com', ' http://www.amazon.com']
    [requests.get(c) for c in url_list]

    for i in range(len(url_list)):
        progress_text.set('Done: {}'.format(i/len(url_list)))
        requests.get(url_list[i])
        print('done')




tk.Button(window, text='download', command=download).pack()


window.mainloop()