<img src="/img/tutorial/generate-clients/image01.png">

You can see those schemas because they were declared with the models in the app.

That information is available in the app's **OpenAPI schema**, and then shown in the API docs (by Swagger UI).

### `response_model` or Return Type

In this case, because the two models are different, if we annotated the function return type as `UserOut`, the editor and tools would complain that we are returning an invalid type, as those are different classes.

That's why in this example we have to declare it in the `response_model` parameter.

But documentation is still missing. Then APISpec was created.

It is a plug-in for many frameworks (and there's a plug-in for Starlette too).

The way it works is that you write the definition of the schema using YAML format inside the docstring of each function handling a route.

And it generates OpenAPI schemas.

That's how it works in Flask, Starlette, Responder, etc.

!!! 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.

## Keçən ayın ən fəal istifadəçiləri

Bu istifadəçilər keçən ay [GitHub-da başqalarının suallarına](help-fastapi.md#help-others-with-questions-in-github){.internal-link target=_blank} ən çox kömək edənlərdir. ☕

{% if people %}
<div class="user-list user-list-center">
{% for user in people.last_month_experts[:10] %}

## Geçen Ayın En Aktif Kullanıcıları

Geçtiğimiz ay boyunca [GitHub'da diğerlerine en çok yardımcı olan](help-fastapi.md#help-others-with-questions-in-github){.internal-link target=_blank} kullanıcılar. ☕

{% if people %}
<div class="user-list user-list-center">
{% for user in people.last_month_experts[:10] %}

!!! tip
    The "PATCH" is the last number, for example, in `0.2.3`, the PATCH version is `3`.

So, you should be able to pin to a version like:

```txt
fastapi>=0.45.0,<0.46.0
```

Breaking changes and new features are added in "MINOR" versions.

!!! tip
    The "MINOR" is the number in the middle, for example, in `0.2.3`, the MINOR version is `2`.

## Upgrading the FastAPI versions

## Proxy with a stripped path prefix

Having a proxy with a stripped path prefix, in this case, means that you could declare a path at `/app` in your code, but then, you add a layer on top (the proxy) that would put your **FastAPI** application under a path like `/api/v1`.

In this case, the original path `/app` would actually be served at `/api/v1/app`.

Even though all your code is written assuming there's just `/app`.

# Advanced Middleware

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md){.internal-link target=_blank} to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares

#### Compare *enumeration members*

You can compare it with the *enumeration member* in your created enum `ModelName`:

```Python hl_lines="17"
{!../../../docs_src/path_params/tutorial005.py!}
```

#### Get the *enumeration value*

You can get the actual value (a `str` in this case) using `model_name.value`, or in general, `your_enum_member.value`:

```Python hl_lines="20"