For that, use the standard Python `typing.List` (or just `list` in Python 3.9 and above):

{* ../../docs_src/extra_models/tutorial004_py39.py hl[18] *}


## Response with arbitrary `dict` { #response-with-arbitrary-dict }

You can also declare a response using a plain arbitrary `dict`, declaring just the type of the keys and values, without using a Pydantic model.

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example:

* `users:read` or `users:write` are common examples.
* `instagram_basic` is used by Facebook / Instagram.
* `https://www.googleapis.com/auth/drive` is used by Google.

/// info

In OAuth2 a "scope" is just a string that declares a specific permission required.

          + "quis in augue. Suspendisse id dui in lorem tristique placerat eget vel risus. Sed "
          + "metus neque, scelerisque in molestie ac, mattis quis lectus. Pellentesque viverra "
          + "justo commodo quam bibendum ut gravida leo accumsan. Nullam malesuada sagittis diam, "
          + "quis suscipit mauris euismod vulputate. Pellentesque ultrices tellus sed lorem "

    /**
     * Invoked just before session is created with a mutable map that carries collected user properties so far.
     *
     * @param userProperties The mutable user properties, never {@code null}.
     * @see #contribute(ProtoSession)
     */
    default void contribute(Map<String, String> userProperties) {}

    /**

///

/// note | Technical Details

You could also use `from starlette.testclient import TestClient`.

**FastAPI** provides the same `starlette.testclient` as `fastapi.testclient` just as a convenience for you, the developer. But it comes directly from Starlette.

///

/// tip

Si vous ne voulez pas leur donner de valeur par défaut mais juste les rendre optionnels, utilisez `None` comme valeur par défaut.

Mais si vous voulez rendre un paramètre de requête obligatoire, vous pouvez juste ne pas y affecter de valeur par défaut :

{* ../../docs_src/query_params/tutorial005.py hl[6:7] *}

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable" { #create-a-dependency-or-dependable }

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

That's it.

**2 lines**.

That doesn't add any extra security to your API, the *path operations* will still be available where they are.

If there's a security flaw in your code, it will still exist.

We can use **OAuth2** to build that with **FastAPI**.

But let's save you the time of reading the full long specification just to find those little pieces of information you need.

Let's use the tools provided by **FastAPI** to handle security.

## How it looks { #how-it-looks }

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

## Create `main.py` { #create-main-py }

# About HTTPS { #about-https }

It is easy to assume that HTTPS is something that is just "enabled" or not.

But it is way more complex than that.

/// tip

If you are in a hurry or don't care, continue with the next sections for step by step instructions to set everything up with different techniques.

///