{* ../../docs_src/body/tutorial001_py310.py hl[5:9] *}

与声明查询参数一样，包含默认值的模型属性是可选的，否则就是必选的。把默认值设为 `None` 可使其变为可选。

例如，上述模型声明如下 JSON "object"（即 Python `dict`）：

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

...由于 `description` 和 `tax` 是可选的（默认值为 `None`），下面的 JSON "object" 也有效：

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

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Functions;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.testing.ClassSanityTester.FactoryMethodReturnsNullException;
import com.google.common.testing.ClassSanityTester.ParameterHasNoDistinctValueException;

 */
package org.codelibs.fess.util;

import java.io.File;
import java.io.FilenameFilter;
import java.nio.file.Path;

import org.codelibs.fess.unit.UnitFessTestCase;
import org.dbflute.optional.OptionalEntity;
import org.junit.jupiter.api.Test;

public class ResourceUtilTest extends UnitFessTestCase {
    @Test
    public void test_resolve() {
        String value;

        value = null;

Ce n'est pas une limitation de **FastAPI**, cela fait partie du protocole HTTP.

///

## Téléversement de fichier facultatif { #optional-file-upload }

Vous pouvez rendre un fichier facultatif en utilisant des annotations de type standard et en définissant une valeur par défaut à `None` :

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

Esto no es una limitación de **FastAPI**, es parte del protocolo HTTP.

///

## Subida de Archivos Opcional { #optional-file-upload }

Puedes hacer un archivo opcional utilizando anotaciones de tipos estándar y estableciendo un valor por defecto de `None`:

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

func DomainPort(domainPort string) EtcdOption {
	return func(args *CoreDNS) {
		args.domainPort = domainPort
	}
}

// CoreDNSPath - custom prefix on etcd to populate DNS
// service records, optional and can be empty.
// if empty then c.prefixPath is used i.e "/skydns"
func CoreDNSPath(prefix string) EtcdOption {
	return func(args *CoreDNS) {
		args.prefixPath = prefix
	}
}

		return errors.New("STS JWT Token has `aud` claim invalid, `aud` must match configured OpenID Client ID")
	}
	if !audValues.Contains(pCfg.ClientID) {
		// if audience claims is missing, look for "azp" claims.
		// OPTIONAL. Authorized party - the party to which the ID
		// Token was issued. If present, it MUST contain the OAuth
		// 2.0 Client ID of this party. This Claim is only needed
		// when the ID Token has a single audience value and that

import org.codelibs.fess.Constants;
import org.codelibs.fess.dict.DictionaryException;
import org.codelibs.fess.dict.DictionaryFile;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.optional.OptionalEntity;

/**
 * Dictionary file for protected words.
 * This class manages the reading, writing, and updating of protected words dictionary files.
 */

# ----------------------------------------------------------------------------
# Maven Start Up Batch script
#
# Required ENV vars:
# ------------------
#   JAVA_HOME - location of a JDK home dir
#
# Optional ENV vars
# -----------------
#   M2_HOME - location of maven2's installed home dir
#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
#     e.g. to debug Maven itself, use

import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * CompactLinkedHashSet is an implementation of a Set, which a predictable iteration order that
 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)