How to properly initialize uWSGI if it's callable is in another function?

Question

Python

uWSGI wants a callable object for input. Right now my code looks like
main.py:
app = create_app()
and is called like this:

uwsgi --http :9000 --wsgi-file main.py --callable app

I want to wrap everything in something like this:

def main():
  app = create_app()

Question. How can I call everything then? After all, the called instance of the application will be in `main()`?