8. Nota que esta *path operation function* usa `def` regular en lugar de `async def`.

    Como siempre, en FastAPI puedes combinar `def` y `async def` según sea necesario.

    Si necesitas un repaso sobre cuándo usar cuál, revisa la sección _"¿Con prisa?"_ en la documentación sobre [`async` y `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

# ボディ - フィールド

`Query`や`Path`、`Body`を使って *path operation関数* のパラメータに追加のバリデーションやメタデータを宣言するのと同じように、Pydanticの`Field`を使ってPydanticモデルの内部でバリデーションやメタデータを宣言することができます。

## `Field`のインポート

まず、以下のようにインポートします:

{* ../../docs_src/body_fields/tutorial001.py hl[4] *}

/// warning | 注意

`Field`は他の全てのもの（`Query`、`Path`、`Body`など）とは違い、`fastapi`からではなく、`pydantic`から直接インポートされていることに注意してください。

///

## モデルの属性の宣言

以下のように`Field`をモデルの属性として使用することができます:

* `close()`: Cierra el archivo.

Como todos estos métodos son métodos `async`, necesitas "await" para ellos.

Por ejemplo, dentro de una *path operation function* `async` puedes obtener los contenidos con:

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

Si estás dentro de una *path operation function* normal `def`, puedes acceder al `UploadFile.file` directamente, por ejemplo:

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

   * loaded) value, or null. Multiple concurrent calls to {@link Cache} lookup methods on an absent
   * value can result in multiple misses, all returning the results of a single cache load
   * operation.
   */
  public long missCount() {
    return missCount;
  }

  /**
   * Returns the ratio of cache requests which were misses. This is defined as {@code missCount /

///

Les réponses générées au format OpenAPI pour cette *opération de chemin* seront :

```JSON hl_lines="3-12"
{
    "responses": {
        "404": {
            "description": "Additional Response",
            "content": {
                "application/json": {

import (
	"fmt"
	"os"
	"path"
)

// Wrapper functions to os.RemoveAll, which calls reliableRemoveAll
// this is to ensure that if there is a racy parent directory
// create in between we can simply retry the operation.
func removeAll(dirPath string) (err error) {
	if dirPath == "" {
		return errInvalidArgument
	}

	if err = checkPathLength(dirPath); err != nil {
		return err
	}

In this case, this `__call__` is what **FastAPI** will use to check for additional parameters and sub-dependencies, and this is what will be called to pass a value to the parameter in your *path operation function* later.

## Parameterize the instance { #parameterize-the-instance }

And now, we can use `__init__` to declare the parameters of the instance that we can use to "parameterize" the dependency:

            throw new SmbException("Integer overflow in file operation");
        }

        // Check bounds
        if (offset + length > fileSize) {
            failedValidations.incrementAndGet();
            log.warn("File operation exceeds file size: offset={}, length={}, size={}", offset, length, fileSize);
            throw new SmbException("File operation exceeds file bounds");
        }
    }

    /**

        CIFSException expectedException = new CIFSException("Watch operation failed");
        when(watchHandle.watch()).thenThrow(expectedException);

        // Execute and verify
        CIFSException thrown = assertThrows(CIFSException.class, () -> {
            watchHandle.watch();
        });

        assertEquals("Watch operation failed", thrown.getMessage());
        verify(watchHandle, times(1)).watch();
    }

    /**
     * Deletes all crawling sessions and their parameters except for the specified active sessions.
     * This is a cleanup operation that removes inactive session data while preserving active ones.
     *
     * @param activeSessionId a set of session IDs to preserve during the cleanup operation
     */
    public void deleteOldSessions(final Set<String> activeSessionId) {
        final List<CrawlingInfo> activeSessionList =