"description": "Production environment"
        }
    ],
    "paths": {
            // More stuff here
    }
}
```

!!! tip
    Notice the auto-generated server with a `url` value of `/api/v1`, taken from the `root_path`.

In the docs UI at <a href="http://127.0.0.1:9999/api/v1/docs" class="external-link" target="_blank">http://127.0.0.1:9999/api/v1/docs</a> it would look like:

    If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

Then you could call that Python program:

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

// As we didn't set the env var, we get the default value

Hello World from Python