To do that, use the standard Python type hint <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note

 * 3. Register with `client.eventListenerFactory(eventListenerFactory)`
 * 4. Launch wireshark if not done externally `val process = eventListenerFactory.launchWireShark()`
 */
@SuppressSignatureCheck
class WireSharkListenerFactory(
  private val logFile: File,
  private val tlsVersions: List<TlsVersion>,
  private val launch: Launch? = null,
) : EventListener.Factory {
  override fun create(call: Call): EventListener {

 * This is for the benefit of container environments that implement code unloading.
 *
 * Most applications should share a process-wide [TaskRunner] and use queues for per-client work.
 */
class TaskRunner(
  val backend: Backend,
  internal val logger: Logger = TaskRunner.logger,
) {
  val lock: ReentrantLock = ReentrantLock()
  val condition: Condition = lock.newCondition()

import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;

/**
 * This class provides a skeletal implementation of the {@code Cache} interface to minimize the
 * effort required to implement this interface.
 *
 * <p>To implement a cache, the programmer needs only to extend this class and provide an
 * implementation for the {@link #put} and {@link #getIfPresent} methods. {@link #getAllPresent} is

import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;
import jakarta.annotation.Resource;

public class OpenSearchUrlQueueService extends AbstractCrawlerService implements UrlQueueService<OpenSearchUrlQueue> {
    private static final Logger logger = LoggerFactory.getLogger(OpenSearchUrlQueueService.class);

    @Resource
    protected OpenSearchDataService dataService;

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.
public class MapPutIfAbsentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutIfAbsent_supportedAbsent() {
    assertNull(

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@code ForwardingSet}.
 *
 * @author Robert Konigsberg
 * @author Louis Wasserman
 */
public class ForwardingSetTest extends TestCase {
  static class StandardImplForwardingSet<T> extends ForwardingSet<T> {
    private final Set<T> backingSet;

    StandardImplForwardingSet(Set<T> backingSet) {
      this.backingSet = backingSet;
    }

    },
}


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: Union[str, None] = None
    scopes: list[str] = []


class User(BaseModel):
    username: str
    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


class UserInDB(User):
    hashed_password: str

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.accesstoken;

/**
 * @author codelibs
 * @author jflute
 */
public class SearchForm {

    public String id;

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.app.web.admin.badword;

/**
 * @author shinsuke
 */
public class DownloadForm {