Fix Python – How do I get Flask to run on port 80?

I have a Flask server running through port 5000, and it’s fine. I can access it at http://example.com:5000
But is it possible to simply access it at http://example.com? I’m assuming that means I have to change the port from 5000 to 80. But when I try that on Flask, I get this error message when I run it.
Traceback (most recent call last):
File “….