#### `Optional`

Вы также можете использовать `Optional`, чтобы объявить, что переменная имеет тип, например, `str`, но это является «необязательным», что означает, что она также может быть `None`:

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

import org.codelibs.fess.opensearch.config.exentity.RelatedContent;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.HtmlResponse;
import org.lastaflute.web.response.render.RenderData;

    return pickInstance(Currency.getAvailableCurrencies(), Currency.getInstance(Locale.US));
  }

  @Empty
  <T> Optional<T> generateJavaOptional() {
    return Optional.empty();
  }

  @Generates
  <T> Optional<T> generateJavaOptional(T value) {
    return Optional.of(value);
  }

  @Generates
  OptionalInt generateOptionalInt() {
    return OptionalInt.of(generateInt());
  }

import org.codelibs.fess.opensearch.config.exentity.WebConfig;
import org.codelibs.fess.util.ParameterUtil;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.optional.OptionalEntity;

import jakarta.annotation.Resource;

/**
 * Service class for managing web crawling configurations.
 * Provides CRUD operations for web configuration settings including

			Key:         config.SubnetSubSys,
			Type:        "string",
			Description: "register Enterprise license for the cluster",
			Optional:    true,
		},
		config.HelpKV{
			Key:         config.CallhomeSubSys,
			Type:        "string",
			Description: "enable callhome to MinIO SUBNET",
			Optional:    true,
		},
		config.HelpKV{
			Key:         config.DriveSubSys,
			Description: "enable drive specific settings",
		},

        with:
          results_file: results.sarif
          results_format: sarif
          publish_results: true

      # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
      # format to the repository Actions tab.
      - name: "Upload artifact"
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2

import org.codelibs.fess.opensearch.config.exentity.KeyMatch;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.HtmlResponse;
import org.lastaflute.web.response.render.RenderData;

     */
    @Size(max = 10000)
    @Required
    public String rt;

    /**
     * Hash value for security or validation purposes.
     * This field is optional and used for request verification.
     */
    public String hash;

    /**
     * Query identifier associated with the search that led to this document access.

import java.util.Locale;

import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.entity.SearchRequestParams;
import org.codelibs.fess.mylasta.action.FessUserBean;
import org.dbflute.optional.OptionalThing;

/**
 * Abstract base class for rank fusion searchers in the Fess search system.
 * Rank fusion searchers are responsible for executing search queries and

    }

    /**
     * Implementation method for reading an XML node from an input stream.
     *
     * @param input the input stream to read from
     * @param locationBuilder optional builder for creating input location objects
     * @return the parsed XML node
     * @throws XMLStreamException if there is an error parsing the XML
     */