توی پایتون 3.6 و بالاتر (از جمله پایتون 3.10) می‌تونی با وارد کردن و استفاده از `Optional` از ماژول `typing` اینو تعریف کنی.

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

استفاده از `Optional[str]` به جای فقط `str` به ویرایشگر کمک می‌کنه خطاهایی که ممکنه فکر کنی یه مقدار همیشه `str` هست رو پیدا کنه، در حالی که می‌تونه `None` هم باشه.

     * @return Java path type associated to the given location
     */
    public static Optional<JavaPathType> valueOf(JavaFileManager.Location location) {
        for (JavaPathType type : JavaPathType.values()) {
            if (location.equals(type.location)) {
                return Optional.of(type);
            }
        }
        return Optional.empty();
    }

    /**

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

O uso de `Optional[str]` em vez de apenas `str` permitirá que o editor o ajude a detectar erros, onde você pode estar assumindo que um valor é sempre um `str`, quando na verdade também pode ser `None`.

 */
package org.apache.maven.api.services;

import java.io.Closeable;
import java.net.URI;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.util.Optional;

import org.apache.maven.api.RemoteRepository;
import org.apache.maven.api.annotations.Consumer;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**

            }

            @Nonnull
            @Override
            public Optional<Project> getProject() {
                return Optional.ofNullable(project);
            }

            @Nonnull
            @Override
            public Optional<Artifact> getRootArtifact() {
                return Optional.ofNullable(rootArtifact);
            }

            @Nonnull
            @Override

		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.26</version>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>commons-logging</groupId>
			<artifactId>commons-logging</artifactId>
			<version>1.3.5</version>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>

   */
  RangeSet<C> complement();

  /**
   * Returns a view of the intersection of this {@code RangeSet} with the specified range.
   *
   * <p>The returned view supports all optional operations supported by this {@code RangeSet}, with
   * the caveat that an {@link IllegalArgumentException} is thrown on an attempt to {@linkplain

#### 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!}
```

     */
    @Nonnull
    DependencyScope getScope();

    /**
     * Returns whether the dependency is optional, mandatory, or of unspecified obligation.
     *
     * @return {@code Boolean.TRUE} and {@code Boolean.FALSE} if optional, or {@code null} if unspecified
     */
    @Nullable
    Boolean getOptional();

    /**
     * {@return transitive dependencies to exclude}
     */

    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: |