## Importe `Field`

Primeiro, você tem que importá-lo:

```Python hl_lines="4"
{!../../docs_src/body_fields/tutorial001.py!}
```

/// warning | "Aviso"

Note que `Field` é importado diretamente do `pydantic`, não do `fastapi` como todo o resto (`Query`, `Path`, `Body`, etc).

///

## Declare atributos do modelo

Você pode então utilizar `Field` com atributos do modelo:

```Python
contents = await myfile.read()
```

在普通 `def` *路径操作函数*  内，则可以直接访问 `UploadFile.file`，例如：

```Python
contents = myfile.file.read()
```

/// note | "`async` 技术细节"

使用 `async` 方法时，**FastAPI** 在线程池中执行文件方法，并 `await` 操作完成。

///

/// note | "Starlette 技术细节"

**FastAPI** 的 `UploadFile` 直接继承自 **Starlette** 的 `UploadFile`，但添加了一些必要功能，使之与 **Pydantic** 及 FastAPI 的其它部件兼容。

///

## 什么是 「表单数据」

   * natural ordering.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableSortedSet#copyOf(Iterable)}
   * instead.
   *
   * <p><b>Note:</b> If {@code elements} is a {@code SortedSet} with an explicit comparator, this
   * method has different behavior than {@link TreeSet#TreeSet(SortedSet)}, which returns a {@code
   * TreeSet} with that comparator.
   *

* **`300`** and above are for "Redirection".  Responses with these status codes may or may not have a body, except for `304`, "Not Modified", which must not have one.
* **`400`** and above are for "Client error" responses. These are the second type you would probably use the most.
    * An example is `404`, for a "Not Found" response.

<dependencies>
  ...
</dependencies>
    ]]></configuration>
    <description>
      <![CDATA[
      This is a set of Artifact instances resolved from the set of dependencies for
      the current project.

      NOTE: This will likely contain much more than the direct dependencies of the
      current POM, since Maven uses transitive, or chained, dependency resolution.
    ]]></description>
  </expression>
  <expression>

        git diff --diff-filter ACMRT --name-only pull_branch^ pull_branch > $BATS_FILE_TMPDIR/changed_files
    else
        # If the branch is not present, then diff against origin/master
        git diff --diff-filter ACMRT --name-only origin/master > $BATS_FILE_TMPDIR/changed_files
    fi
}

# Note: this is excluded on the full code base, since any submitted code must
# have passed Google's internal style guidelines.

Note: each component can be installed in parallel with an existing Istio 1.0 or 1.1 installation in
`istio-system`. The new components will not interfere with existing apps, but can interoperate,
and it is possible to gradually move apps from Istio 1.0/1.1 to the new environments and
across environments ( for example canary -> prod )

   * provided key-value mapping, this method has no effect.
   *
   * <p>Note that a successful call to this method could cause the size of the bimap to increase by
   * one, stay the same, or even decrease by one.
   *
   * <p><b>Warning:</b> If an existing entry with this value is removed, the key for that entry is
   * discarded and not returned.
   *
   * @param key the key with which the specified value is to be associated

```

////

👥 ✔️ ❎ 🔢 💲 `None` 🔢 ⏮️ `Query()`, 👥 💪 🔜 ⚒ 🔢 💲 ⏮️ 🔢 `Query(default=None)`, ⚫️ 🍦 🎏 🎯 ⚖ 👈 🔢 💲.

:

```Python
q: Union[str, None] = Query(default=None)
```

...⚒ 🔢 📦, 🎏:

```Python
q: Union[str, None] = None
```

& 🐍 3️⃣.1️⃣0️⃣ & 🔛:

```Python
q: str | None = Query(default=None)
```

...⚒ 🔢 📦, 🎏:

```Python

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        logMessage(
                Diagnostic.Kind.NOTE, "Processing " + roundEnv.getRootElements().size() + " classes");

        for (Element element : roundEnv.getElementsAnnotatedWith(Named.class)) {
            if (element instanceof TypeElement typeElement) {