{* ../../docs_src/dataclasses_/tutorial001.py hl[1,7:12,19:20] *}

这还是借助于 **Pydantic** 及其<a href="https://pydantic-docs.helpmanual.io/usage/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">内置的 `dataclasses`</a>。

因此，即便上述代码没有显式使用 Pydantic，FastAPI 仍会使用 Pydantic 把标准数据类转换为 Pydantic 数据类（`dataclasses`）。

并且，它仍然支持以下功能：

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import java.io.Closeable
import java.io.IOException
import java.io.InputStream
import java.io.InputStreamReader
import java.io.Reader
import java.nio.charset.Charset
import okhttp3.internal.charsetOrUtf8
import okhttp3.internal.chooseCharset
import okhttp3.internal.closeQuietly

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.crawler.exception;

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * An exception that indicates multiple crawling access exceptions occurred.
 * This exception holds an array of Throwable objects representing the individual causes.

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.artifact.versioning;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;

package tests_test

import (
	"testing"

	"gorm.io/gorm"
	. "gorm.io/gorm/utils/tests"
)

func TestUpdateHasManyAssociations(t *testing.T) {
	user := *GetUser("update-has-many", Config{})

	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	user.Pets = []*Pet{{Name: "pet1"}, {Name: "pet2"}}
	if err := DB.Save(&user).Error; err != nil {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.File;
import java.io.IOException;
import okhttp3.Cache;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public final class CacheResponse {
  private final OkHttpClient client;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;
import javax.xml.stream.XMLStreamException;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.crawler.extractor.impl;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import org.apache.commons.compress.archivers.ArchiveStreamFactory;

 [okhttp]: https://square.github.io/okhttp/
 [okhttp_312x]: https://github.com/square/okhttp/tree/okhttp_3.12.x
 [okio]: https://github.com/square/okio
 [post_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/PostExample.java
 [r8_proguard]: https://square.github.io/okhttp/features/r8_proguard/
 [recipes]: https://square.github.io/okhttp/recipes/

 * under the License.
 */
package org.apache.maven.artifact;

import javax.inject.Inject;
import javax.inject.Named;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;