You might want to try their services and follow their guides:

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}

[data-ty] {
    display: block;
    line-height: 2;
}

[data-ty]:before {
    /* Set up defaults and ensure empty lines are displayed. */
    content: '';
    display: inline-block;
    vertical-align: middle;
}

[data-ty="input"]:before,
[data-ty-prompt]:before {
    margin-right: 0.75em;
    color: var(--color-text-subtle);
}

[data-ty="input"]:before {
    content: '$';
}

Because we are passing it as a **value to an argument** instead of putting it in a **type annotation**, we have to use `Union` even in Python 3.10.

If it was in a type annotation we could have used the vertical bar, as:

```Python
some_variable: PlaneItem | CarItem
```

### Dependency Injection

FastAPI includes an extremely easy to use, but extremely powerful <abbr title='also known as "components", "resources", "services", "providers"'><strong>Dependency Injection</strong></abbr> system.

* Even dependencies can have dependencies, creating a hierarchy or **"graph" of dependencies**.
* All **automatically handled** by the framework.

加上来自 Starlette（包括 **session cookie**）的所有安全特性。

所有的这些都是可复用的工具和组件，可以轻松与你的系统，数据仓库，关系型以及 NoSQL 数据库等等集成。



### 依赖注入

FastAPI 有一个使用非常简单，但是非常强大的<abbr title='也叫做 "components", "resources", "services", "providers"'><strong>依赖注入</strong></abbr>系统。

* 甚至依赖也可以有依赖，创建一个层级或者**“图”依赖**。
* 所有**自动化处理**都由框架完成。
* 所有的依赖关系都可以从请求中获取数据，并且**增加了路径操作**约束和自动文档生成。
* 即使在依赖项中被定义的*路径操作* 也会**自动验证**。
* 支持复杂的用户身份认证系统，**数据库连接**等等。

➕ 🌐 💂‍♂ ⚒ ⚪️➡️ 💃 (🔌 **🎉 🍪**).

🌐 🏗 ♻ 🧰 & 🦲 👈 ⏩ 🛠️ ⏮️ 👆 ⚙️, 📊 🏪, 🔗 & ☁ 💽, ♒️.

### 🔗 💉

FastAPI 🔌 📶 ⏩ ⚙️, ✋️ 📶 🏋️ <abbr title='also known as "components", "resources", "services", "providers"'><strong>🔗 💉</strong></abbr> ⚙️.

* 🔗 💪 ✔️ 🔗, 🏗 🔗 ⚖️ **"📊" 🔗**.
* 🌐 **🔁 🍵** 🛠️.
* 🌐 🔗 💪 🚚 💽 ⚪️➡️ 📨 &amp; **↔ ➡ 🛠️** ⚛ &amp; 🏧 🧾.
* **🏧 🔬** *➡ 🛠️* 🔢 🔬 🔗.

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        </span> Subscribe to the <strong>FastAPI and friends</strong> newsletter 🎉
      </a>
    </div>
    <div class="item">

Dado que estamos passando-o como um **valor para um argumento** em vez de colocá-lo em uma **anotação de tipo**, precisamos usar `Union` mesmo no Python 3.10.

Se estivesse em uma anotação de tipo, poderíamos ter usado a barra vertical, como:

```Python
some_variable: PlaneItem | CarItem
```