And you can also declare body parameters as optional, by setting the default to `None`:

{* ../../docs_src/body_multiple_params/tutorial001_an_py310.py hl[18:20] *}

/// note

Notice that, in this case, the `item` that would be taken from the body is optional. As it has a `None` default value.

///

## Multiple body parameters { #multiple-body-parameters }

Having `str | None` will allow your editor to give you better support and detect errors.

///

## Additional validation { #additional-validation }

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated` { #import-query-and-annotated }

To achieve that, first import:

* `Query` from `fastapi`

   *     network
   * @since 23.0
   */
  Optional<E> edgeConnecting(N nodeU, N nodeV);

  /**
   * Returns the single edge that directly connects {@code endpoints} (in the order, if any,
   * specified by {@code endpoints}), if one is present, or {@code Optional.empty()} if no such edge
   * exists.
   *
   * <p>If this network is directed, the endpoints must be ordered.

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

    if (allowsNullKeys) {
      boolean unused = map.containsKey(null);
    } else {
      try {
        boolean unused2 = map.containsKey(null);
      } catch (NullPointerException optional) {
      }
    }
    assertInvariants(map);
  }

  public void testContainsValue() {
    Map<K, V> map;
    V unmappedValue;
    try {
      map = makePopulatedMap();

* パラメータが **Pydantic モデル**型で宣言された場合、リクエスト**ボディ**として解釈されます。

/// note | 備考

FastAPIは、`= None`があるおかげで、`q`がオプショナルだとわかります。

`Optional[str]` の`Optional` はFastAPIでは使用されていません（FastAPIは`str`の部分のみ使用します）。しかし、`Optional[str]` はエディタがコードのエラーを見つけるのを助けてくれます。

///

## Pydanticを使わない方法

 * the License.
 */

package com.google.common.util.concurrent.internal;


/**
 * A future that, if it fails, may <i>optionally</i> provide access to the cause of the failure.
 *
 * <p>This class is used only for micro-optimization. Standard {@code Future} utilities benefit from

    }

    @Test
    @DisplayName("createContext accepts null/empty optional parameters")
    void createContext_edge_parameters_ok() throws Exception {
        TestCredentials creds = new TestCredentials("D", false, false, new Subject(), false);
        // Intentionally pass null/empty values for optional parameters; expect no exception
        SSPContext ctx1 = creds.createContext(mockContext, null, "", null, false);

import org.codelibs.fess.opensearch.config.exbhv.JobLogBhv;
import org.codelibs.fess.opensearch.config.exentity.JobLog;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.optional.OptionalEntity;

import jakarta.annotation.Resource;

/**
 * Service class for managing job logs in the Fess application.
 * Provides functionality to create, read, update, and delete job log entries,

 * limitations under the License.
 */

package com.google.common.io;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.io.SourceSinkFactory.ByteSourceFactory;
import com.google.common.io.SourceSinkFactory.CharSourceFactory;
import java.io.BufferedReader;