クエリパラメータの宣言と同様に、モデル属性がデフォルト値を持つ場合は必須ではありません。そうでなければ必須です。単にオプションにするには `None` を使用してください。

例えば、上記のモデルは次のようなJSON「`object`」（またはPythonの `dict`）を宣言します:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...`description` と `tax` はオプション（デフォルト値が `None`）なので、このJSON「`object`」も有効です:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

### Faça o deploy da sua aplicação (opcional) { #deploy-your-app-optional }

Você pode, opcionalmente, fazer o deploy da sua aplicação FastAPI na [FastAPI Cloud](https://fastapicloud.com); acesse e entre na lista de espera, se ainda não entrou. 🚀

* `tags: List[str] = []` için default, boş bir list’tir: `[]`.

Ancak gerçekte kaydedilmedilerse, bunları sonuçtan çıkarmak isteyebilirsiniz.

Örneğin NoSQL veritabanında çok sayıda optional attribute içeren modelleriniz varsa, default değerlerle dolu çok uzun JSON response’ları göndermek istemeyebilirsiniz.

### `response_model_exclude_unset` parametresini kullanın { #use-the-response-model-exclude-unset-parameter }

    }

    /**
     * Generates a complete URL with context path and cache-busting timestamp.
     *
     * @param input the relative URL path starting with '/'
     * @return complete URL with context path and optional timestamp parameter
     * @throws IllegalArgumentException if input is null or doesn't start with '/'
     */
    public static String url(final String input) {
        if (input == null) {

import org.codelibs.fess.unit.UnitFessTestCase;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.bhv.readable.CBCall;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.optional.OptionalEntity;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestInfo;
import org.opensearch.index.query.QueryBuilder;
import org.opensearch.search.sort.FieldSortBuilder;

import java.util.LinkedHashSet;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * CompactHashSet is an implementation of a Set. All optional operations (adding and removing) are
 * supported. The elements can be any objects.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)

 * already present in the multimap change in a manner that affects {@code equals} comparisons. Use
 * caution if mutable objects are used as keys in a {@code Multimap}.
 *
 * <p>All methods that modify the multimap are optional. The view collections returned by the
 * multimap may or may not be modifiable. Any modification method that is not supported will throw
 * {@link UnsupportedOperationException}.
 *

	OrigVolume string             `msg:"ov"`
	FilePath   string             `msg:"fp"`
	UpdateOpts UpdateMetadataOpts `msg:"uo"`
	FI         FileInfo           `msg:"fi"`
}

// UpdateMetadataOpts provides an optional input to indicate if xl.meta updates need to be fully synced to disk.
type UpdateMetadataOpts struct {
	NoPersistence bool `msg:"np"`
}

// CheckPartsHandlerParams are parameters for CheckPartsHandler

	}
	return data
}

// ScanLines is a split function for a [Scanner] that returns each line of
// text, stripped of any trailing end-of-line marker. The returned line may
// be empty. The end-of-line marker is one optional carriage return followed
// by one mandatory newline. In regular expression notation, it is `\r?\n`.
// The last non-empty line of input will be returned even if it has no
// newline.

これは **FastAPI** の制限ではなく、HTTP プロトコルの仕様です。

///

## 任意のファイルアップロード { #optional-file-upload }

標準の型アノテーションを使い、デフォルト値を `None` に設定することで、ファイルを任意にできます:

{* ../../docs_src/request_files/tutorial001_02_an_py310.py hl[9,17] *}

## 追加メタデータつきの `UploadFile` { #uploadfile-with-additional-metadata }