老师，我写的程序为啥爬不出数据

import threading
from multiprocessing import Queue

from threading import Thread

import requests
from lxml import etree

from study_crawl_douban.handle_mongo import douban_mongo

page_flag = False
data_flag = False


# 页码处理类
class Crawl_page(Thread):
   # 重写父类的方法
   def __init__(self, thread_name, page_queue, data_queue):
       super(Crawl_page, self).__init__()
       self.thread_name = thread_name
       self.page_queue = page_queue
       self.data_queue = data_queue

       self.header = {
           "Accept": " text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
           "Accept-Encoding": " gzip, deflate, br",
           "Accept-Language": " zh-CN,zh;q=0.9",
           "Cache-Control": " no-cache",
           "Connection": " keep-alive",
           "Cookie": " bid=UK3_qCqd8Tw; __utmc=30149280; __utmz=30149280.1589176061.1.1.utmcsr=class.imooc.com|utmccn=(referral)|utmcmd=referral|utmcct=/lesson/1100; __utmc=223695111; __utmz=223695111.1589176061.1.1.utmcsr=class.imooc.com|utmccn=(referral)|utmcmd=referral|utmcct=/lesson/1100; __gads=ID=3a0d842ebc5e8488:T=1589176028:S=ALNI_MbmOwssmmLmbX5t1P8Hx-VVMX7-Ug; ct=y; _pk_ref.100001.4cf6=%5B%22%22%2C%22%22%2C1589283906%2C%22https%3A%2F%2Fclass.imooc.com%2Flesson%2F1100%22%5D; _pk_ses.100001.4cf6=*; ap_v=0,6.0; __utma=30149280.1537622081.1589176061.1589249515.1589283907.3; __utmb=30149280.0.10.1589283907; __utma=223695111.1653981003.1589176061.1589249515.1589283907.3; __utmb=223695111.0.10.1589283907; _pk_id.100001.4cf6=d54cf7120f674951.1589176061.3.1589283922.1589249514.; __yadk_uid=EtEnWgLqtZb6nxHLeCnqXg0D9BV7P9yU",
           "Host": " movie.douban.com",
           "Pragma": " no-cache",
           "Referer": " https://movie.douban.com/top250?start=25&filter=",
           "Sec-Fetch-Dest": " document",
           "Sec-Fetch-Mode": " navigate",
           "Sec-Fetch-Site": " same-origin",
           "Sec-Fetch-User": " ?1",
           "Upgrade-Insecure-Requests": " 1",
           "User-Agent": " Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36",
       }

   def run(self):
       print("当前处理页码的任务为：{}".format(self.thread_name))
       while not page_flag:
           # Queue队列在put或者get的时候，需要设置block
           # 默认为True，则在队列为空的时候会暂停进行等待，需要设置为false
           # 当前队列没有数据或者数据已满的时候会抛出异常，empty或者full
           try:
               page = self.page_queue.get(block=False)
               page_url = 'https://movie.douban.com/top250?start=' + str(page) + '&filter='
               print("当前url为：{}".format(page_url))

               # 设置代理
               # proxy = {
               #     'http': 'http://HIIH05A84N30E6ED:1A6A62A96423AFB9@http-dyn.abuyun.com:9020',
               #     'https': 'https://HIIH05A84N30E6ED:1A6A62A96423AFB9@http-dyn.abuyun.com:9020',
               # }

               # 请求网页
               response = requests.get(url=page_url, headers=self.header)
               response.encoding = 'gbk'
               # 将请求到的文本文件放入数据列表中
               self.data_queue.put(response.text)
           except:
               pass


# 文本处理类
class Crawl_html(Thread):
   # 重写父类方法
   def __init__(self, thread_name, data_queue, lock):
       super(Crawl_html, self).__init__()
       self.thread_name = thread_name
       self.data_queue = data_queue
       self.lock = lock

   def run(self):
       print("当前处理文本的线程为:{}".format(self.thread_name))
       while not data_flag:
           try:
               text = self.data_queue.get(block=False)
               result = self.parse(text)
               while self.lock:
                   douban_mongo.insert(result)
           except:
               pass

   def parse(self, text1):
       # 将html实例化
       douban_html = etree.HTML(text1)
       all_message = douban_html.xpath('//li/div[@class="item"]')
       douban_list = []
       for item in all_message:
           info = {
               'movie_name': item.xpath('.//img/@alt'),
               'actors_information': item.xpath('.//p/text()'),
               'score': item.xpath('.//span[@class="rating_num"]'),
               'evaluate': item.xpath('.//span[@class="inq"]'),
               'from_url': item.xpath('.//a/@href')
           }

           douban_list.append(info)

       return douban_list


def main():
   # 定义两个队列，存放页码的队列，存放文本的队列
   page_queue = Queue()
   data_queue = Queue()

   # 定义一个锁
   lock = threading.Lock()

   # 将页码存入到页码队列中
   for page in range(0, 250, 25):
       page_queue.put(page)

   print("当前页码的总量为：{}".format(page_queue.qsize()))

   # 开启三个线程，用来处理页码数据
   page_list = ["页码线程1号", "页码线程2号", "页码线程3号"]
   page_thread_list = []
   for thread_page_name in page_list:
       thread_page = Crawl_page(thread_page_name, page_queue, data_queue)
       thread_page.start()
       page_thread_list.append(thread_page)

   # 开启三个线程，用来处理文本数据
   text_list = ["文本线程1号", "文本线程2号", "文本线程3号"]
   text_thread_list = []
   for thread_text_name in text_list:
       thread_text = Crawl_html(thread_text_name, data_queue, lock)
       thread_text.start()
       text_thread_list.append(thread_text)

   # 设置线程退出机制
   global page_flag
   while not page_queue.empty():
       pass
   page_flag = True

   # 结束页码处理线程
   for page_thread_join in page_thread_list:
       page_thread_join.join()
       print(page_thread_join.thread_name, "已经停止")

   # 设置线程退出机制
   global data_flag
   while not data_queue.empty():
       pass
   data_flag = True

   # 结束页码处理线程
   for text_thread_join in text_thread_list:
       text_thread_join.join()
       print(text_thread_join.thread_name, "已经停止")


if __name__ == '__main__':
   main()