问Python松弛客户端oauth.access调用返回'invalid_code‘错误

EN

import os
import slack
from flask import Flask, request
app = Flask(__name__)

SLACK_CLIENT_ID = os.environ['SLACK_CLIENT_ID']
SLACK_CLIENT_SECRET = os.environ['SLACK_CLIENT_SECRET']

@app.route('/install', methods=['GET', 'POST'])
def install():
    # Retrieve the auth code from the request params
    auth_code = request.args['code']

    # An empty string is a valid token for this request
    client = slack.WebClient(token='')

    # Request the auth tokens from Slack
    response = client.oauth_access(
        client_id=SLACK_CLIENT_ID,
        client_secret=SLACK_CLIENT_SECRET,
        code=auth_code
    )

    print(response)

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

slack.errors.SlackApiError: The request to the Slack API failed.
The server responded with: {'ok': False, 'error': 'invalid_code', 'warning': 'superfluous_charset', 'response_metadata': {'warnings': ['superfluous_charset']}}