from typing import Optional

from fastapi import Depends, FastAPI, Query, status
from fastapi.testclient import TestClient

app = FastAPI()


def _get_client_key(client_id: str = Query(...)) -> str:
    return f"{client_id}_key"


def _get_client_tag(client_id: Optional[str] = Query(None)) -> Optional[str]:
    if client_id is None:
        return None
    return f"{client_id}_tag"


@app.get("/foo")
def foo_handler(

    private static Optional<String> lookupMessage(int code) {
        int[] codes = WinError.WINERR_CODES;
        String[] msgs = WinError.WINERR_MESSAGES;
        for (int i = 0; i < codes.length; i++) {
            if (codes[i] == code) {
                return Optional.of(msgs[i]);
            }
        }
        return Optional.empty();
    }

    }

    @Override
    public Language language() {
        return (language != null) ? language : SourceRoot.super.language();
    }

    @Override
    public Optional<String> module() {
        return Optional.ofNullable(moduleName);
    }

    @Override
    public PathMatcher matcher(Collection<String> defaultIncludes, boolean useDefaultExcludes) {
        return null; // Not used for this test.
    }

        this.prompter = prompter;
    }

    @Override
    public String description() {
        return "Secure console password prompt";
    }

    @Override
    public Optional<String> configTemplate() {
        return Optional.empty();
    }

    @Override
    public String handle(String config) throws SecDispatcherException {
        if (NAME.equals(config)) {
            try {

    BeanConfigurationRequest setClassLoader(ClassLoader classLoader);

    /**
     * Gets the optional preprocessor for configuration values.
     *
     * @return The preprocessor for configuration values or {@code null} if none.
     */
    BeanConfigurationValuePreprocessor getValuePreprocessor();

    /**
     * Sets the optional preprocessor for configuration values.
     *

        BinaryIO,
        Doc("The standard Python file object (non-async)."),
    ]
    filename: Annotated[Optional[str], Doc("The original file name.")]
    size: Annotated[Optional[int], Doc("The size of the file in bytes.")]
    headers: Annotated[Headers, Doc("The headers of the request.")]
    content_type: Annotated[
        Optional[str], Doc("The content type of the request, from the headers.")
    ]

    async def write(
        self,

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.execution;

import java.util.Optional;

import org.apache.maven.lifecycle.LifecycleExecutionException;
import org.apache.maven.model.Dependency;
import org.apache.maven.project.MavenProject;
import org.junit.jupiter.api.BeforeEach;

이 응용 프로그램을 예로 들어보겠습니다:

{* ../../docs_src/query_params_str_validations/tutorial001.py hl[9] *}

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

    </dependency>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t08-d</artifactId>
      <version>1.1</version>
      <type>jar</type>
      <scope>compile</scope>
      <optional>false</optional>
    </dependency>
  </dependencies>

      </dependency>
      <dependency>
        <groupId>maven-test</groupId>
        <artifactId>t06-d</artifactId>
        <version>1.0</version>
        <scope>test</scope>
        <optional>false</optional>
      </dependency>
    </dependencies>
  </dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t06-a</artifactId>
      <version>1.0</version>