Sie sehen eine einfache Seite wie:

<img src="/img/tutorial/websockets/image01.png">

Sie können Nachrichten in das Eingabefeld tippen und absenden:

<img src="/img/tutorial/websockets/image02.png">

Und Ihre **FastAPI**-Anwendung mit WebSockets antwortet:

<img src="/img/tutorial/websockets/image03.png">

Sie können viele Nachrichten senden (und empfangen):

<img src="/img/tutorial/websockets/image04.png">

    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Coverage">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">
    <img src="https://img.shields.io/pypi/v/fastapi?color=%2334D058&label=pypi%20package" alt="Package version">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">

{% if sponsors %}
{% for sponsor in sponsors.gold -%}
<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>
{% endfor -%}
{%- for sponsor in sponsors.silver -%}
<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>
{% endfor %}
{% endif %}

<!-- /sponsors -->

{% for sponsor in sponsors.gold -%}
<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}"></a>
{% endfor %}
{% endif %}

### Silber Sponsoren

{% if sponsors %}
{% for sponsor in sponsors.silver -%}
<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}"></a>
{% endfor %}
{% endif %}

{% if people %}
{% if people.sponsors_50 %}

<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>
{% endfor %}
{% endif %}

{% if sponsors.silver %}

### Silver Sponsors

{% for sponsor in sponsors.silver -%}
<a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>
{% endfor %}
{% endif %}

    }

    private void assertImageSize(File file, int width, int height) throws IOException {
        BufferedImage img = ImageIO.read(file);
        logger.debug("width: {}, height: {}", img.getWidth(), img.getHeight());
        assertEquals("Image Width", width, img.getWidth());
        assertEquals("Image Height", height, img.getHeight());
    }

这两者不一样。

我们用的是冒号（`:`），不是等号（`=`）。

而且添加类型提示一般不会改变原来的运行结果。

现在假设我们又一次正在创建这个函数，这次添加了类型提示。

在同样的地方，通过 `Ctrl+Space` 触发自动补全，你会发现：

<img src="https://fastapi.tiangolo.com/img/python-types/image02.png">

这样，你可以滚动查看选项，直到你找到看起来眼熟的那个：

<img src="https://fastapi.tiangolo.com/img/python-types/image03.png">

## 更多动机

下面是一个已经有类型提示的函数：

```Python hl_lines="1"
{!../../../docs_src/python_types/tutorial003.py!}

    assert response.status_code == 200, response.text
    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_img():
    shutil.copy("./docs/en/docs/img/favicon.png", "./image.png")
    response = client.get("/items/foo?img=1")
    assert response.status_code == 200, response.text
    assert response.headers["Content-Type"] == "image/png"
    assert len(response.content)

You go with your crush to get fast food, you stand in line while the cashier takes the orders from the people in front of you. 😍

<img src="/img/async/concurrent-burgers/concurrent-burgers-01.png" class="illustration">

Then it's your turn, you place your order of 2 very fancy burgers for your crush and you. 🍔🍔

<img src="/img/async/concurrent-burgers/concurrent-burgers-02.png" class="illustration">

    <img src="https://coverage-badge.samuelcolvin.workers.dev/tiangolo/fastapi.svg" alt="Coverage">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">
    <img src="https://img.shields.io/pypi/v/fastapi?color=%2334D058&label=pypi%20package" alt="Package version">
</a>
<a href="https://pypi.org/project/fastapi" target="_blank">