</dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t06-d</artifactId>
        <version>1.2</version>
        <scope>test</scope>
        <optional>false</optional>
      </dependency>
    </dependencies>
  </dependencyManagement>

```Python hl_lines="9"
{!../../docs_src/query_params_str_validations/tutorial001.py!}
```

쿼리 매개변수 `q`는 `Optional[str]` 자료형입니다. 즉, `str` 자료형이지만 `None` 역시 될 수 있음을 뜻하고, 실제로 기본값은 `None`이기 때문에 FastAPI는 이 매개변수가 필수가 아니라는 것을 압니다.

/// note | "참고"

FastAPI는 `q`의 기본값이 `= None`이기 때문에 필수가 아님을 압니다.

`Optional[str]`에 있는 `Optional`은 FastAPI가 사용하는게 아니지만, 편집기에게 더 나은 지원과 오류 탐지를 제공하게 해줍니다.

///

## 추가 검증

from typing import Optional


def say_hi(name: Optional[str]):

from typing import Optional

import pytest
from fastapi import Cookie, FastAPI, Header, Path, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/hidden_cookie")
async def hidden_cookie(
    hidden_cookie: Optional[str] = Cookie(default=None, include_in_schema=False),
):
    return {"hidden_cookie": hidden_cookie}


@app.get("/hidden_header")
async def hidden_header(

from typing import Optional

from pydantic import BaseModel


class User(BaseModel):
    name: str

			Description: "Enterprise license for the cluster" + defaultHelpPostfix(config.License),
			Optional:    true,
			Sensitive:   true,
		},
		config.HelpKV{
			Key:         config.APIKey,
			Type:        "string",
			Description: "Enterprise license API key for the cluster" + defaultHelpPostfix(config.APIKey),
			Optional:    true,
			Sensitive:   true,
		},
		config.HelpKV{
			Key:         config.Proxy,

    id: build-scan-url
    attributes:
      label: Build scan URL (optional)
      description: |
        You can run your build command with `--scan` to publish a Build Scan to [scans.gradle.com](https://scans.gradle.com/).
    validations:
      required: false
  - type: textarea
    id: environment
    attributes:
      label: Your Environment (optional)
      description: |

from typing import Dict, List, Optional, Tuple

import pytest
from fastapi import FastAPI, Query
from pydantic import BaseModel


def test_invalid_sequence():
    with pytest.raises(AssertionError):
        app = FastAPI()

        class Item(BaseModel):
            title: str

        @app.get("/items/")
        def read_items(q: List[Item] = Query(default=None)):
            pass  # pragma: no cover

#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_ARGS          (Optional) Arguments passed to Maven before CLI arguments.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.

        stablePublicInterface = instanceScopedPool.get(StablePublicInterface.name)

        apiClass.changeStatus >> JApiChangeStatus.MODIFIED
        apiClass.oldClass >> Optional.of(oldBase)
        apiClass.newClass >> Optional.of(newBase)

        internalInterface.name = replaceAsInternal(internalInterface.name)

        interfaces = ['internal': internalInterface,