I've made a Python API file for fetching a resource. If the resource doesn't exist, I want to return "404 Not Found". I have tried Flask's abort(404), but the NotFound error is caught at some point and I get a TypeError instead, resulting in a 500 Server Error from Zero. Here is the stack trace:

werkzeug.exceptions.NotFound: 404 Not Found: The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.
[2020年06月05日 20:40:01,549] ERROR in app: Exception on /video/foobar/ [GET]
Traceback (most recent call last):
 File "/home/tomas/.local/lib/python3.8/site-packages/flask/app.py", line 2446, in wsgi_app
 response = self.full_dispatch_request()
 File "/home/tomas/.local/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
 return self.finalize_request(rv)
 File "/home/tomas/.local/lib/python3.8/site-packages/flask/app.py", line 1967, in finalize_request
 response = self.make_response(rv)
 File "/home/tomas/.local/lib/python3.8/site-packages/flask/app.py", line 2096, in make_response
 raise TypeError(
TypeError: The view function did not return a valid response. The function either returned None or ended without a return statement.

Is this a bug? Or is there a different way to do it?