Facebook Messenger聊天机器人代码UnboundLocalE

Question

使用以下代码，我设置了一个flask应用程序：

https://gist.github.com/ugik/a218a599b1af0ea06b1b38e3a5132078#file-flaskfbmapi-ai-rig

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

# FB messenger credentials
ACCESS_TOKEN = "EAAKsKOJ37rUBAKVZAQ21bn...UsZCXx6UWqQ6XuQr7OHnBYL3xD3Sy5u1ZAZCwip0XnTAHq25CsIpxRsbxZALRHOOguKm2unY7I06LRAZDZD"

# api.ai credentials
CLIENT_ACCESS_TOKEN = "78c0e0...d9404a2"
ai = apiai.ApiAI(CLIENT_ACCESS_TOKEN)

app = Flask(__name__)

@app.route('/', methods=['GET'])
def verify():
    # our endpoint echos back the 'hub.challenge' value specified when we setup the webhook
    if request.args.get("hub.mode") == "subscribe" and request.args.get("hub.challenge"):
        if not request.args.get("hub.verify_token") == 'foo':
            return "Verification token mismatch", 403
        return request.args["hub.challenge"], 200

    return 'Hello World (from Flask!)', 200

def reply(user_id, msg):
    data = {
        "recipient": {"id": user_id},
        "message": {"text": msg}
    }
    resp = requests.post("https://graph.facebook.com/v2.6/me/messages?access_token=" + ACCESS_TOKEN, json=data)
    print(resp.content)


@app.route('/', methods=['POST'])
def handle_incoming_messages():
    data = request.json
    sender = data['entry'][0]['messaging'][0]['sender']['id']
    message = data['entry'][0]['messaging'][0]['message']['text']

    # prepare API.ai request
    req = ai.text_request()
    req.lang = 'en'  # optional, default value equal 'en'
    req.query = message

    # get response from API.ai
    api_response = req.getresponse()
    responsestr = api_response.read().decode('utf-8')
    response_obj = json.loads(responsestr)
    if 'result' in response_obj:
        response = response_obj["result"]["fulfillment"]["speech"]
    reply(sender, response)

    return "ok"

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

但是，在第51行，我的服务器日志中有一个错误：

UnboundLocalError: local variable 'response' referenced before assignment

据我所知，根本原因是“response”只在if语句中定义，但是，由于它不是我的代码，所以在外部定义变量时遇到了问题。如果我把这个代码放在第48行之后，这行行吗

response=response\u obj[“结果”][“实现”][“讲话”]