在电报上连续收到消息

Question

from flask import Flask
from flask import request,jsonify
import requests
import json

app = Flask(__name__)

url = ''
token = ''

def send_message(chat_id,text):
    URL = url+token+'sendMessage'
    answer = {'chat_id': chat_id, 'text': text}
    r = requests.post(URL,json = answer)
    return ''


@app.route('/', methods = ['GET','POST'])
def index():
    if request.method == 'POST':
        r = request.get_json()
        chat_id = r['message']['chat']['id']
        text = "how are you?"
        send_message(chat_id,text)
    else:
        return "hello world"

if __name__ == '__main__':
    app.run()

当我在设置webhook后运行此操作时，我不断收到文本“你好吗？”不断。我该如何解决？我看到2个答案告诉他们返回200 Ok。有人可以帮忙吗？