Issue with the "Getting Started" doc

[JonDevOps]

I found an issue with this document.

Title: Getting Started
Location: https://fly.io/docs/django/getting-started/ exactly at https://fly.io/docs/django/getting-started/#django-deployment-checklist
Source: https://github.com/superfly/docs/blob/main/django/getting-started/index.html.md

Describe the issue

I started tutorial and i noticed when i deployed it i wasnt looking at the server 8000. But after What i noticed is when i get to the deployment section of the tutorial and I update the ALLOWED_HOSTS it breaks the app.

So when i add import os & APP_NAME = os.environ.get("FLY_APP_NAME") the code still works after saving. But when i add ALLOWED_HOSTS = [f"{APP_NAME}.fly.dev"] it stops working, and i add it exactly how it is in your example repo. I put import os at the top and APP_NAME above allowed hosts.

I put a screenshot of the error im getting in the comment below ind a pdf embedded in the comment

Addtional info

[JonDevOps]

Heres a full image of the error message I recieved after changing the allowed hosts. Remember it should say like "Hello, Fly!". I guess the good thing is even though it throughs the error the project did actually deploy. I just need to know why this error occurs, if i should worry about it, and if so how do i fix it.