"这是代码"

import os
import redis
import flask
import json
import urllib.parse
from flask import Flask, Response, request, render_template, abort
from flask_cors import CORS, cross_origin
#from flask.ext.cors import CORS, cross_origin

app = Flask(__name__)
app.config['CORS_HEADERS'] = 'Content-Type'
redis_handle = redis.Redis('localhost')
requiredFields = ("id", "title", "name")  # fields required for user object

@app.route('/')
@cross_origin()
def hello():
    return 'Hello World!'

@app.route('/users/<user_id>', methods=['GET'])
@cross_origin()
def get_user(user_id):
    response = {}
    # user_id = request.args.get("id")
    user = redis_handle.get(user_id)
    if not user:
        response["msg"] = "no user found"
        return Response(json.dumps(response), status=404, mimetype="application/json")
    return user

@app.route('/users', methods=['POST'])
@cross_origin()
def save_user():
    data = request.get_json(force=True)
    response = {}
    if all(field in data for field in requiredFields):
        redis_handle.set(data["id"], json.dumps(data))
        return Response(status=201)
    else:
        missing_key = str([val for val in requiredFields if val not in dict(data).keys()])
        response["msg"] = "required key " + missing_key + " not found"
        return Response(json.dumps(response), status=400)

@app.route('/users/<user_id>', methods=['DELETE'])
@cross_origin()
def delete_user(user_id):
    response = {}
    resp = redis_handle.delete(user_id)
    if resp == 0:
        response["msg"] = "no such entity found"
        status = 404
    else:
        response["msg"] = "Delete op is successful"
        status = 200
    return Response(json.dumps(response), status=status)

@app.route('/clear', methods=['GET'])
@cross_origin()
def clear_data():
    redis_handle.flushall()
    return "ok!"

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

据我所知，我甚至还包括了method =“POST”，但仍然不知道哪里出了问题。
我试着用redis，python，flask创建一个小的crud应用程序，但是没有遇到这个问题。有人能告诉我我哪里做错了吗？