from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security import OAuth2PasswordBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl="/token",
    description="OAuth2PasswordBearer security scheme",
    auto_error=False,
)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    if token is None:

    </dependency>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t05-d</artifactId>
      <version>1.1</version>
      <type>jar</type>
      <scope>compile</scope>
      <optional>false</optional>
    </dependency>
  </dependencies>

    </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>

            }

            @Override
            public <T> Optional<T> lookupOptional(Class<T> type) {
                return Optional.empty();
            }

            @Override
            public <T> Optional<T> lookupOptional(Class<T> type, String name) {
                return Optional.empty();
            }

            @Override

  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t05-d</artifactId>
      <version>1.1</version>
      <type>jar</type>
      <scope>compile</scope>
      <optional>true</optional>
    </dependency>
  </dependencies>

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

     * These arguments allow for customization of the JVM environment in which Maven will run.
     *
     * @return an Optional containing the list of extra JVM arguments, or empty if not specified
     */
    @Nonnull
    Optional<List<String>> jvmArguments();

        if (!(member instanceof JApiClass)) {
            return null
        }

        if (!changed(member)) {
            return null
        }

        Optional<CtClass> oldClass = member.oldClass
        Optional<CtClass> newClass = member.newClass
        if (!oldClass.isPresent() || !newClass.isPresent()) {
            // breaking change would be reported
            return null
        }

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

`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।

      return new Chopper() {
        @Override
        Optional<String> chop(String str) {
          return i.chop(str).or(you.chop(str));
        }
      };
    }

    abstract Optional<String> chop(String str);

    static Chopper suffix(String suffix) {
      return new Chopper() {
        @Override
        Optional<String> chop(String str) {
          if (str.endsWith(suffix)) {