if (executionEvent.getType() == ExecutionEvent.Type.SessionEnded) {
                usedTypes.clear();
            }
        }
    }

    @Override
    public Optional<Type> lookup(String id) {
        return Optional.of(require(id));
    }

    @Override
    @Nonnull
    public Type require(String id) {
        nonNull(id, "id");
        return usedTypes.computeIfAbsent(id, i -> {

ingInputs=this.dependingInputs||[],this.dependingInputs.push(c)})})},c=function(b,c){var d=function(){var c=a(this),d=c.valAttr("optional-if-answered"),e=!1,f=!!a.formUtils.getValue(c);f||(a.each(a.split(d),function(c,d){var f=b.find('[name="'+d+'"]');if(e=!!a.formUtils.getValue(f))return!1}),e&&c.valAttr("skipped",1))},e=function(){var d=a(this),e=d.valAttr("optional-if-answered");a.each(a.split(e),function(d,e){var f=b.find('[name="'+e+'"]'),g=!!a.formUtils.getValue(f);g||a.formUtils.dialogs.r...

			Description: `customize scanner speed (default|slowest|slow|fast|fastest)` + defaultHelpPostfix(Speed),
			Optional:    true,
			Type:        "string",
		},
		config.HelpKV{
			Key:         ExcessVersions,
			Description: `alert per object beyond this many versions` + defaultHelpPostfix(ExcessVersions),
			Optional:    true,
			Type:        "int",
		},
		config.HelpKV{
			Key:         ExcessFolders,

      </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: |