=== "Python 3.8+"

    ```Python
    q: Annotated[Union[str, None]] = None
    ```

Both of those versions mean the same thing, `q` is a parameter that can be a `str` or `None`, and by default, it is `None`.

Now let's jump to the fun stuff. 🎉

## Add `Query` to `Annotated` in the `q` parameter

Now that we have this `Annotated` where we can put more metadata, add `Query` to it, and set the parameter `max_length` to 50:

Then the cashier 💁 says "I'm finished with doing the burgers" by putting your number on the counter's display, but you don't jump like crazy immediately when the displayed number changes to your turn number. You know no one will steal your burgers because you have the number of your turn, and they have theirs.

Using Linux containers has several advantages including **security**, **replicability**, **simplicity**, and others.

!!! tip
    In a hurry and already know this stuff? Jump to the [`Dockerfile` below 👇](#build-a-docker-image-for-fastapi).

<details>
<summary>Dockerfile Preview 👀</summary>

```Dockerfile
FROM python:3.9

WORKDIR /code