# 请求体 - 嵌套模型

使用 **FastAPI**，你可以定义、校验、记录文档并使用任意深度嵌套的模型（归功于Pydantic）。

## List 字段

你可以将一个属性定义为拥有子元素的类型。例如 Python `list`：

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

这将使 `tags` 成为一个由元素组成的列表。不过它没有声明每个元素的类型。

## 具有子类型的 List 字段

但是 Python 有一种特定的方法来声明具有子类型的列表：

### 从 typing 导入 `List`

首先，从 Python 的标准库 `typing` 模块中导入 `List`：

{* ../../docs_src/body_nested_models/tutorial002.py hl[1] *}

  @CollectionSize.Require(absent = ZERO)
  public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {
      resetContainer();

      K k = entry.getKey();
      V v = entry.getValue();

      List<V> values = multimap().get(k);
      List<V> expectedValues = copyToList(values);

      assertTrue(multimap().put(k, v));

import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArrayList;

import org.apache.maven.project.DependencyResolutionResult;
import org.apache.maven.project.MavenProject;

public class DefaultMavenExecutionResult implements MavenExecutionResult {
    private MavenProject project;

    private List<MavenProject> topologicallySortedProjects = Collections.emptyList();

     * <p>The default implementation returns an empty list, which means to apply a language-dependent pattern.
     * For example, for the Java language, the pattern includes all files with the {@code .java} suffix.</p>
     *
     * @see java.nio.file.FileSystem#getPathMatcher(String)
     */
    default List<String> includes() {
        return List.of();
    }

    /**
     * {@return the list of patterns for the files to exclude}

 */
package org.codelibs.fess.crawler.service.impl;

import static org.codelibs.opensearch.runner.OpenSearchRunner.newConfigs;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;

import org.codelibs.fess.crawler.client.FesenClient;

        assertFalse(response1.hasError());

        List<Throwable> errors = new ArrayList<>();
        errors.add(new Exception("Test error"));
        SuggestIndexResponse response2 = new SuggestIndexResponse(10, 5, errors, 100);
        assertTrue(response2.hasError());
    }

    @Test
    public void test_getErrors() throws Exception {
        List<Throwable> errors = new ArrayList<>();

                  protected Set<String> create(String[] elements) {
                    return new SafeTreeSet<>(asList(elements));
                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return new ArrayList<>(Sets.newTreeSet(insertionOrder));
                  }
                })
            .withFeatures(
                CollectionSize.ANY,

public final class ProjectSegment {
    private final MavenProject project;

    private final TaskSegment taskSegment;

    private final MavenSession session;

    private final List<MavenProject> nonTransitiveUpstreamProjects;

    private final List<MavenProject> transitiveUpstreamProjects;

    public ProjectSegment(MavenProject project, TaskSegment taskSegment, MavenSession copiedSession) {
        this.project = project;

                }
            }
        }

        private void mergePluginContainerPlugins(PluginContainer target, PluginContainer source) {
            List<Plugin> src = source.getPlugins();
            if (!src.isEmpty()) {
                List<Plugin> tgt = target.getPlugins();

                Map<Object, Plugin> managedPlugins = new LinkedHashMap<>(src.size() * 2);

        project.addAttachedArtifact(artifact);
    }

    @Override
    public void addResource(
            MavenProject project, String resourceDirectory, List<String> includes, List<String> excludes) {
        Resource resource = new Resource();
        resource.setDirectory(resourceDirectory);
        resource.setIncludes(includes);
        resource.setExcludes(excludes);