谷歌应用引擎上的Python 3 https请求不起作用

我是新手为python部署应用程序引擎的解决方案，并尝试使一个简单的http请求工作，但徒劳无功 . 我正在使用试用版 . 我已按照此操作使用vendoring指令安装请求和requests-toolbelt . https://cloud.google.com/appengine/docs/standard/python/issue-requests

这是我的代码，以确保我做得对 . 当我使用谷歌 Cloud 外壳部署解决方案时，它可以很好地构建，但是当查看部署的站点时，我只会收到错误502 Bad Gateway nginx . 如果有任何帮助，可以在app引擎错误报告仪表板中找到错误

AttributeError：'NoneType'对象没有属性'add_extra_file'

load_wsgi（/env/lib/python3.6/site-packages/gunicorn/workers/base.py:148）

Traceback（最近一次调用最后一次）：

文件“/home/vmagent/app/main.py”，第21行：在import_app上的requests_toolbelt.adapters.appengine.monkeypatch（）（/env/lib/python3.6/site-packages/gunicorn/util.py:352 ）在load_wsgiapp（/env/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py:52）加载时（/env/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py ：65）在wsgi（/env/lib/python3.6/site-packages/gunicorn/app/base.py:67）at load_wsgi（/env/lib/python3.6/site-packages/gunicorn/workers/base的.py：135）

我尝试了很多来自stackoverflow的解决方案，但无法找到解决方案 . 下面是代码 . main.js，app.yaml，requirements.txt

import logging
import requests
import requests_toolbelt.adapters.appengine
from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello():
    """Return a friendly HTTP greeting."""
        # Use the App Engine Requests adapter. This makes sure that Requests uses
        # URLFetch.
        requests_toolbelt.adapters.appengine.monkeypatch()
        url = 'http://www.google.com/humans.txt'
        response = requests.get(url)
        response.raise_for_status()
        #url = 'http://www.google.com/humans.txt'


    return response.text


@app.errorhandler(500)
def server_error(e):
    logging.exception('An error occurred during a request.')
    return """
    An internal error occurred: <pre>{}</pre>
    See logs for full stacktrace.
    """.format(e), 500


if __name__ == '__main__':
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine. See entrypoint in app.yaml.
    app.run(host='127.0.0.1', port=8080, debug=True)

requirements.txt Flask == 0.12.2 gunicorn == 19.7.1 App . YAML

runtime: python
env: flex
entrypoint: gunicorn -b :$PORT main:app

runtime_config:
  python_version: 3