また、デフォルトの`None`を設定することで、ボディパラメータをオプションとして宣言することもできます:

{* ../../docs_src/body_multiple_params/tutorial001.py hl[19,20,21] *}

/// note | 備考

この場合、ボディから取得する`item`はオプションであることに注意してください。デフォルト値は`None`です。

///

## 複数のボディパラメータ

上述の例では、*path operations*は`item`の属性を持つ以下のようなJSONボディを期待していました:

```JSON
{
    "name": "Foo",
    "description": "The pretender",

```

`Optional[str]` ব্যবহার করা মানে হল শুধু `str` নয়, এটি হতে পারে `None`-ও, যা আপনার এডিটরকে সেই ত্রুটিগুলি শনাক্ত করতে সাহায্য করবে যেখানে আপনি ধরে নিচ্ছেন যে একটি মান সবসময় `str` হবে, অথচ এটি `None`-ও হতে পারেও।

`Optional[Something]` মূলত `Union[Something, None]`-এর একটি শর্টকাট, এবং তারা সমতুল্য।

এর মানে হল, Python 3.10-এ, আপনি টাইপগুলির ইউনিয়ন ঘোষণা করতে `Something | None` ব্যবহার করতে পারেন:

//// tab | Python 3.10+

### Node Binaries

filename | sha512 hash
-------- | -----------
[kubernetes-node-linux-amd64.tar.gz](https://dl.k8s.io/v1.22.17/kubernetes-node-linux-amd64.tar.gz) | 1e3db1b374a7d7584d23190f64f41717a383ae531a67b7081b685fc9f4d081741374589b632643e7ef88b3ba2850f388b9e7dda0cee1ed8a4f8581d75905a89b

  <modelVersion>4.0.0</modelVersion>
  <groupId>com.google.guava</groupId>
  <artifactId>guava-parent</artifactId>
  <version>999.0.0-HEAD-android-SNAPSHOT</version>
  <packaging>pom</packaging>
  <name>Guava Maven Parent</name>
  <description>Parent for guava artifacts</description>
  <url>https://github.com/google/guava</url>
  <properties>
    <!--

  <modelVersion>4.0.0</modelVersion>
  <groupId>com.google.guava</groupId>
  <artifactId>guava-parent</artifactId>
  <version>999.0.0-HEAD-jre-SNAPSHOT</version>
  <packaging>pom</packaging>
  <name>Guava Maven Parent</name>
  <description>Parent for guava artifacts</description>
  <url>https://github.com/google/guava</url>
  <properties>
    <!--

#!groovy

pipeline {
  agent none
  // save some io during the build
  options {
    skipDefaultCheckout()
    durabilityHint('PERFORMANCE_OPTIMIZED')
    disableRestartFromStage()
  }
  stages {
    stage("Build / Test - JDK17") {
      agent { node { label 'ubuntu' } }
      steps {
        timeout(time: 210, unit: 'MINUTES') {
          checkout scm
          mavenBuild("jdk_17_latest", "")
          script {

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")

### Node Binaries

filename | sha512 hash
-------- | -----------
[kubernetes-node-linux-amd64.tar.gz](https://dl.k8s.io/v1.31.12/kubernetes-node-linux-amd64.tar.gz) | 17e6290eb983b623fb61e7707cfde4ad57d181372e10a400001bacceb07c35739c5e7d51d521f5bf5776d4fe15786b09ad0a7d37b26197fdaf4cea293f20b88f

        channel = "flakiness-detection",
        extraParameters = "--checks none --rerun --cross-version-only",
    ),
    AD_HOC(
        displayName = "AdHoc Performance Test",
        timeout = 30,
        channel = "adhoc",
        extraParameters = "--checks none",
    ),
}

enum class Trigger {
    NEVER,
    EACH_COMMIT,
    DAILY,
    WEEKLY,
}

// present only in memory, it helps to generate the zip stream.
type dummyFileInfo struct {
	name    string
	size    int64
	mode    os.FileMode
	modTime time.Time
	isDir   bool
	sys     any
}

func (f dummyFileInfo) Name() string       { return f.name }
func (f dummyFileInfo) Size() int64        { return f.size }
func (f dummyFileInfo) Mode() os.FileMode  { return f.mode }