}

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

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

            @Nonnull
            @Override

#### 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!}
```

    }

    @Override
    public Optional<Long> lengthIfKnown() {
      long result = 0L;
      for (CharSource source : sources) {
        Optional<Long> lengthIfKnown = source.lengthIfKnown();
        if (!lengthIfKnown.isPresent()) {
          return Optional.absent();
        }
        result += lengthIfKnown.get();
      }
      return Optional.of(result);
    }

    @Override

    }

    @Override
    public Optional<Long> lengthIfKnown() {
      long result = 0L;
      for (CharSource source : sources) {
        Optional<Long> lengthIfKnown = source.lengthIfKnown();
        if (!lengthIfKnown.isPresent()) {
          return Optional.absent();
        }
        result += lengthIfKnown.get();
      }
      return Optional.of(result);
    }

    @Override

     */
    @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: |

    /**
     * Creates a default toolchain instance using system defaults.
     *
     * @return Optional containing the default toolchain if available
     * @throws ToolchainFactoryException if default toolchain creation fails
     */
    @Nonnull
    Optional<Toolchain> createDefaultToolchain() throws ToolchainFactoryException;

   */
  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

#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_ARGS          (Optional) Arguments passed to Maven before CLI arguments.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.

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

Sử dụng `Optional[str]` thay cho `str` sẽ cho phép trình soạn thảo giúp bạn phát hiện các lỗi mà bạn có thể gặp như một giá trị luôn là một `str`, trong khi thực tế nó rất có thể là `None`.