How to use "Generating a URL"?

I saw Generating a URL in the document, but I didn’t quite understand (the transfer of processing power between response functions).

async def index(request):
    # generate a URL for the endpoint `post_handler`
    url = app.url_for('post_handler', post_id=5)

    # Redirect to `/posts/5`
    return redirect(url)

async def post_handler(request, post_id):
    return text(f"{post_id}")

I think it should return 5 instead of redirecting the link

I am unsure as to what you’re expecting… return redirect(url) will return a redirect.