static images not showing in flask when deploying with vercel

Question

I am trying to deploy my flask application in Vercel. I followed this tutorial: https://dev.to/andrewbaisden/how-to-deploy-a-python-flask-app-to-vercel-2o5k

It mainly works for deploying my app, but unfortunately my static images/videos are not showing. My dir structure is:

root
----- index.py
----- vercel.json
----- requirements.txt
----- another files
----- static -
             video.webm
             video.mp4
----- templates

My vercel.json looks like this:

{
    "version": 2,
    "builds": [
        {
            "src": "./index.py",
            "use": "@vercel/python"
        },
        {
            "src": "/static/**",
            "use": "@vercel/static"
        }
    ],
    "routes": [
        {
            "src": "/(.*)",
            "dest": "index.py"
        }
    ]
}

I dont know whats happening, because templates are working and routes too, but static files are not showing at all.