Pythpn multithreaded crawler queue queue cannot return data

import requests
from lxml import html
from requests.exceptions import RequestException
import time
import queue
import threading

class MyThread (threading.Thread):

def __init__(self, func):
    threading.Thread.__init__(self)
    self.func = func

def run(self):
    self.func()

def worker ():

while not q.empty():
    page = q.get()  -sharp 
    print(" : " + str(page) + "url")
    headers = {"user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36"}
    main_page_url = "https://www.qiushibaike.com/hot/page/" + str(page)
    url_list = []
    try:
        rep = requests.get(main_page_url, headers = headers)
        time.sleep(1)
        if rep.status_code == 200:
            print("" +str(page) + "")
            con = rep.content
            sel = html.fromstring(con)
            urls = sel.xpath("//a[@class="contentHerf"]/@href")
            for url in urls:                    
                message_url = "https://www.qiushibaike.com" + url
                url_list.append(message_url)
            print(url_list)
            **-sharpreturn url_list**
                            
    except RequestException:
        print("")
        return None
    time.sleep(1)

def main ():

threads = []
-sharpall_url = []
-sharpurl_list = worker()
for page in range(1, 7):    -sharp6
    q.put(page)
for i in range(threadNum): -sharp2
    thread = MyThread(worker)
    thread.start()
    -sharpall_url.append(url_list)
    threads.append(thread)
for thread in threads:
    thread.join()   -sharp22

if name ="_ _ main__":

q = queue.Queue()
threadNum = 2   -sharp 
main()

in worker, each return only runs the first two threads and then ends. Normally, it runs two threads and then continues to run two threads. Or the way I return the data is wrong.