#### Possibly `None` (Optional)

Ви можете оголосити, що значення може мати тип, наприклад `str`, але також може бути `None`.

У Python 3.6 і вище (включаючи Python 3.10) ви можете оголосити його, імпортувавши та використовуючи `Optional` з модуля `typing`.

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

    }

    private static void trimValues(MavenProperties configProps) {
        configProps.replaceAll((k, v) -> v.trim());
    }

    private static String nextLocation(StringTokenizer st) {
        boolean optional = false;
        String retVal = null;

        if (st.countTokens() > 0) {
            String tokenList = "?\",";
            StringBuilder tokBuf = new StringBuilder(10);
            String tok;

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.mylasta.direction.sponsor;

import java.util.TimeZone;

import org.dbflute.optional.OptionalObject;
import org.dbflute.optional.OptionalThing;
import org.dbflute.util.DfTypeUtil;
import org.lastaflute.web.ruts.process.ActionRuntime;
import org.lastaflute.web.servlet.request.RequestManager;

        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
        }

from typing import Optional, Union

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class ExtendedItem(Item):
    age: int


@app.post("/items/")
def save_union_different_body(item: Union[ExtendedItem, Item]):
    return {"item": item}


client = TestClient(app)

- [ ] Run `mvn dbflute:freegen` to regenerate Java classes
- [ ] Run `mvn clean package` to rebuild project
- [ ] Test language selection in admin UI
- [ ] (Optional) Configure OpenSearch analyzers in `fess.json`
- [ ] (Optional) Add custom dictionaries for search analysis
- [ ] Verify all UI pages display correctly in new language
- [ ] Test error messages and form validation

      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)) {

        void shouldBeApplicableWhenPluginsOptionTrue() {
            UpgradeOptions options = mock(UpgradeOptions.class);
            when(options.plugins()).thenReturn(Optional.of(true));
            when(options.all()).thenReturn(Optional.empty());

            UpgradeContext context = createMockContext(options);

            assertTrue(strategy.isApplicable(context), "Strategy should be applicable when --plugins is true");

    }

    public Stream<BuildStep> steps(MavenProject project) {
        return Optional.ofNullable(plan.get(project))
                .map(m -> m.values().stream())
                .orElse(Stream.empty());
    }

    public Optional<BuildStep> step(MavenProject project, String name) {
        return Optional.ofNullable(plan.get(project)).map(m -> m.get(name));
    }

def get_current_user(oauth_header: Optional[str] = Security(reusable_oauth2)):
    if oauth_header is None:
        return None
    user = User(username=oauth_header)
    return user


@app.post("/login")
def login(form_data: OAuth2PasswordRequestFormStrict = Depends()):
    return form_data


@app.get("/users/me")
def read_users_me(current_user: Optional[User] = Depends(get_current_user)):