!!! tip "İpucu"
    Parametrenin başında `/home/johndoe/myfile.txt` yolunda olduğu gibi (`/`) işareti ile birlikte kullanmanız gerektiği durumlar olabilir.

    Bu durumda, URL, `files` ile `home` arasında iki eğik çizgiye (`//`) sahip olup `/files//home/johndoe/myfile.txt` gibi gözükecektir.

## Özet

**FastAPI** ile kısa, sezgisel ve standart Python tip tanımlamaları kullanarak şunları elde edersiniz:

## About third party integrations

In this example we are using the OAuth2 "password" flow.

This is appropriate when we are logging in to our own application, probably with our own frontend.

Because we can trust it to receive the `username` and `password`, as we control it.

---

"_**Netflix** is pleased to announce the open-source release of our **crisis management** orchestration framework: **Dispatch**! [built with **FastAPI**]_"

Next, it 🤖 takes the first task to finish (let's say, our "slow-file" 📝) and continues whatever it had to do with it.

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

```Python hl_lines="22"
{!../../../docs_src/events/tutorial003.py!}
```

"_If anyone is looking to build a production Python API, I would highly recommend **FastAPI**. It is **beautifully designed**, **simple to use** and **highly scalable**, it has become a **key component** in our API first development strategy and is driving many automations and services such as our Virtual TAC Engineer._"

# Classes as Dependencies

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example

In the previous example, we were returning a `dict` from our dependency ("dependable"):

=== "Python 3.10+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="11"

---

"_**Netflix** is pleased to announce the open-source release of our **crisis management** orchestration framework: **Dispatch**! [built with **FastAPI**]_"

---

<div style="text-align: left; direction: ltr;">"<strong>Netflix</strong> is pleased to announce the open-source release of our <strong>crisis management</strong> orchestration framework: <strong>Dispatch</strong>! [built with <strong>FastAPI</strong>]"</div>

    ```Python hl_lines="15"
    {!> ../../../docs_src/dependencies/tutorial008d.py!}
    ```

Now the client will get the same *HTTP 500 Internal Server Error* response, but the server will have our custom `InternalError` in the logs. 😎

## Execution of dependencies with `yield`