* Les valeurs de ce dictionnaire sont de type `float`.

#### `Optional`

Vous pouvez aussi utiliser `Optional` pour déclarer qu'une variable a un type, comme `str` mais qu'il est "optionnel" signifiant qu'il pourrait aussi être `None`.

{*../../docs_src/python_types/tutorial009.py hl[1,4] *}

   * dependence on a type/method which GWT doesn't support, it is sufficient to simply reference the
   * unsupported type/method. E.g. "Class.isInstance".
   *
   * <p>As of Guava 20.0, this value is optional. We encourage authors who wish to describe why an
   * API is {@code @GwtIncompatible} to instead leave an implementation comment.
   */
  String value() default "";

	metricsRouter.Handle(prometheusMetricsV2ResourcePath, auth(metricsResourceHandler()))

	// Metrics v3
	metricsV3Server := newMetricsV3Server(auth)

	// Register metrics v3 handler. It also accepts an optional query
	// parameter `?list` - see handler for details.
	metricsRouter.Methods(http.MethodGet).Path(metricsV3Path + "{pathComps:.*}").Handler(metricsV3Server)

/**
 * Custom exception class for handling errors related to Curl operations.
 * This class extends {@link RuntimeException} and provides constructors
 * to create an exception instance with a message and an optional cause.
 *
 * <p>Usage examples:</p>
 * <pre>
 *     throw new CurlException("Error message");
 *     throw new CurlException("Error message", cause);
 * </pre>
 *
 * @see RuntimeException
 */

        // As a side effect it will log the optional projects that could not be resolved.
        projectSelector.getOptionalProjectsBySelectors(request, session.getAllProjects(), allOptionalSelectors);
    }

    /**
     * Check whether any of the requested optional profiles were not activated or deactivated.
     * @param session the Maven session.
     * @param profileActivation the requested optional and required profiles.
     */

///

/// note

**FastAPI** saura que `q` est optionnel grâce au `=None`.

Le `Optional` dans `Optional[str]` n'est pas utilisé par **FastAPI** (**FastAPI** n'en utilisera que la partie `str`), mais il servira tout de même à votre éditeur de texte pour détecter des erreurs dans votre code.

///

import org.codelibs.fess.opensearch.config.exentity.BoostDocumentRule;
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;

 * </p>
 * <ul>
 *   <li>{@code GCS_PROJECT_ID}: The Google Cloud project ID.</li>
 *   <li>{@code GCS_ENDPOINT}: Custom endpoint URL (optional, for testing with fake-gcs-server).</li>
 *   <li>{@code GCS_CREDENTIALS_FILE}: Path to service account JSON file (optional).</li>
 * </ul>
 *
 * <p>
 * The {@link GcsURLConnection} class handles the actual connection and data retrieval from the storage service.
 * </p>
 */

     *
     * @param projectId the GCS project ID
     * @param bucket the bucket name
     * @param endpoint the custom endpoint URL (optional, for fake-gcs-server etc.)
     * @param credentialsPath the path to the credentials JSON file (optional)
     */
    public GcsStorageClient(final String projectId, final String bucket, final String endpoint, final String credentialsPath) {
        this.bucket = bucket;

      <artifactId>commons-cli</artifactId>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <optional>true</optional>
    </dependency>

    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>