{!> ../../docs_src/dependencies/tutorial001.py!}
```

////

But then we get a `dict` in the parameter `commons` of the *path operation function*.

And we know that editors can't provide a lot of support (like completion) for `dict`s, because they can't know their keys and value types.

We can do better...

## What makes a dependency

Up to now you have seen dependencies declared as functions.

    this.withLock {
      runningSyncCalls.add(call)
    }

  /** Used by [AsyncCall.run] to signal completion. */
  internal fun finished(call: AsyncCall) {
    call.callsPerHost.decrementAndGet()
    finished(runningAsyncCalls, call)
  }

  /** Used by [Call.execute] to signal completion. */
  internal fun finished(call: RealCall) {
    finished(runningSyncCalls, call)
  }

            // Since the value of oldFuture can only ever be immediateFuture(null) or setFuture of
            // a future that eventually came from immediateFuture(null), this doesn't leak
            // throwables or completion values.
            newFuture.setFuture(oldFuture);
          } else if (outputFuture.isCancelled() && taskExecutor.trySetCancelled()) {

import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionException;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Future} that accepts completion listeners. Each listener has an associated executor, and
 * it is invoked using this executor once the future's computation is {@linkplain Future#isDone()

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

* no <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

🚥 👆 ❎ 🏎 ✳, 👆 💪 ❎ 🛠️ ⏮️:

<div class="termy">

```console
$ typer --install-completion

zsh completion installed in /home/user/.bashrc.
Completion will take effect once you restart the terminal.
```

</div>

### 📱 &amp; 🩺 🎏 🕰

🚥 👆 🏃 🖼 ⏮️, ✅:

<div class="termy">

```console

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

* en <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

![editor support](https://fastapi.tiangolo.com/img/vscode-completion.png)

*  <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">🗒</a>:

![editor support](https://fastapi.tiangolo.com/img/pycharm-completion.png)

👆 🔜 🤚 🛠️ 📟 👆 5️⃣📆 🤔 💪 ⏭. 🖼, `price` 🔑 🔘 🎻 💪 (👈 💪 ✔️ 🐦) 👈 👟 ⚪️➡️ 📨.

    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

Again, doing just that declaration, with **FastAPI** you get:

* Editor support (completion, etc.), even for nested models
* Data conversion
* Data validation
* Automatic documentation

## Special types and validation

如果你已经安装 Typer CLI ，则可以使用以下命令安装自动补全功能：

<div class="termy">

```console
$ typer --install-completion

zsh completion installed in /home/user/.bashrc.
Completion will take effect once you restart the terminal.
```

</div>

### 文档架构

文档使用 <a href="https://www.mkdocs.org/" class="external-link" target="_blank">MkDocs</a> 生成。