返回类型必须是字符串、字典、元组、响应实例或可调用的 WSGI，但它是一个 TypeError

Question

I am new to python, I am trying to add data into a collection:

import pymongo 
from bson.objectid import ObjectId

client = pymongo.MongoClient("mongodb://localhost:27017/")
db = client['inventory']
collection = db['items']

class Inventory():

     def insert(self, data):
        response = collection.insert_one(data)
        return response.inserted_id

However I keep getting the same error:

Traceback (most recent call last):
  File "/home/vitor/.local/lib/python3.7/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/vitor/.local/lib/python3.7/site-packages/flask/app.py", line 1952, in full_dispatch_request
    return self.finalize_request(rv)
  File "/home/vitor/.local/lib/python3.7/site-packages/flask/app.py", line 1967, in finalize_request
    response = self.make_response(rv)
  File "/home/vitor/.local/lib/python3.7/site-packages/flask/app.py", line 2130, in make_response
    " {rv.__class__.__name__}.".format(rv=rv)
TypeError: The view function did not return a valid response. The return type must be a string, dict, tuple, Response instance, or WSGI callable, but it was a TypeError.

I believe the solution is simple, but I can't seem to find it. I wold appreciate any help.

EDIT:

On request of amanb , here are my routes and index.

index:

from flask import Flask, request
from src.routes.inventory import inventory_route

app.register_blueprint(inventory_route, url_prefix='/inventory')

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

routes:

from flask import Flask, Blueprint
from src.controllers.inventory import inventoryController

controller = inventoryController()

inventory_route = Blueprint('inventory_route', __name__)

@inventory_route.route("/addItem", methods=['POST'])
def addItem():
    response = controller.addItem()
    return response

Answer 1

After a couple of more tries, I've discovered that the data being passed was wrong for some reason. I was using Insomnia to pass data but for some mysterious reason the data inside the request body was giving this error. I just hard codded the data into the insert_one() method and it worked.

response = collection.insert_one({ "name": "new Item" })