This is "synchronous" work, you are "synchronized" with the cashier/cook 👨‍🍳. You have to wait 🕙 and be there at the exact moment that the cashier/cook 👨‍🍳 finishes the burgers and gives them to you, or otherwise, someone else might take them.

<img src="/img/async/parallel-burgers/parallel-burgers-04.png" class="illustration">

Но внутреннее устройство **конкурентности** и **параллелизма** довольно разное.

Чтобы это понять, представьте такую картину:

### Конкурентные бургеры

<!-- The gender neutral cook emoji "🧑‍🍳" does not render well in browsers. In the meantime, I'm using a mix of male "👨‍🍳" and female "👩‍🍳" cooks. -->

The section:

```Python
from .routers import items, users
```

means:

* Starting in the same package that this module (the file `app/main.py`) lives in (the directory `app/`)...
* look for the subpackage `routers` (the directory at `app/routers/`)...
* and from it, import the submodule `items` (the file at `app/routers/items.py`) and `users` (the file at `app/routers/users.py`)...

* 🔧 Add `CITATION.cff` file for academic citations. PR [#10496](https://github.com/tiangolo/fastapi/pull/10496) by [@tiangolo](https://github.com/tiangolo).
* 🐛 Fix overriding MKDocs theme lang in hook. PR [#10490](https://github.com/tiangolo/fastapi/pull/10490) by [@tiangolo](https://github.com/tiangolo).

You declare the dependency as the type of the parameter, and you use `Depends()` without any parameter, instead of having to write the full class *again* inside of `Depends(CommonQueryParams)`.

The same example would then look like:

=== "Python 3.10+"

    ```Python hl_lines="19"
    {!> ../../../docs_src/dependencies/tutorial004_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="19"

This could be especially useful during testing, as it's very easy to override a dependency with your own custom settings.

### The config file

Coming from the previous example, your `config.py` file could look like:

```Python hl_lines="10"
{!../../../docs_src/settings/app02/config.py!}
```

Notice that now we don't create a default instance `settings = Settings()`.

### The main app file

It will look like this:

<img src="/img/tutorial/sql-databases/image02.png">

Because it is installed in the local project, you probably wouldn't be able to call that command directly, but you would put it on your `package.json` file.

It could look like this:

```JSON  hl_lines="7"
{
  "name": "frontend-app",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {

!!! tip
    If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

## Separating tests

In a real application, you probably would have your tests in a different file.

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:

<img src="/img/tutorial/behind-a-proxy/image03.png">

!!! tip
    The docs UI will interact with the server that you select.

### Disable automatic server from `root_path`