What does " test_config=None" mean in a flask app ?

Question

What does " test_config=None" mean in a flask app ? I read the flask documentation but i really didn't understand
Here's an example code:

import os
from flask import Flask

def create_app(test_config=None):
app = Flask (__name__)

return app

Answer 1

In this example it does nothing, the function just takes that argument but doesn't use it, you can call it whatever you want.
Link the part of the documentation where you read this and I'll analyze it

Answer 2

Bagon Thanks for replying,
I mean what does it do in general ? It's usage ?

Here's the documentation
https://flask.palletsprojects.com/en/1.1.x/tutorial/factory/

Answer 3

Marina Khamis you can load a configuration file and override some default keys, not that useful for small projects but might be handy in large ones