# 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] *}

        final ListResultBean<FileConfig> list = fileConfigBhv.selectList(cb -> {
            cb.query().setName_Equal(name);
            cb.query().addOrderBy_SortOrder_Asc();
        });
        if (list.isEmpty()) {
            return OptionalEntity.empty();
        }
        return OptionalEntity.of(list.get(0));
    }

    /**
     * Stores a file configuration in the database.

        return this;
    }

    /**
     * Gets the list of active features.
     *
     * @return A list of active features.
     */
    public List<String> activeFeatures() {
        return activeFeatures;
    }

    /**
     * Sets the list of active features.
     *
     * @param activeFeatures A list of active features.
     * @return This query builder.
     */

     *
     * @param repositories a list of repositories
     * @return corresponding effective repositories
     * @since 3.6.1
     */
    public List<ArtifactRepository> getEffectiveRepositories(List<ArtifactRepository> repositories) {
        if (repositories == null) {
            return null;
        }

        Map<String, List<ArtifactRepository>> reposByKey = new LinkedHashMap<>();

     */
    public SearchRenderData() {
        // Default constructor
    }

    /**
     * Sets the list of search result documents.
     *
     * @param documentItems The list of search result documents
     */
    public void setDocumentItems(final List<Map<String, Object>> documentItems) {
        this.documentItems = documentItems;
    }

    /**

  E[] createArray(int length);

  /**
   * Returns the iteration ordering of elements, given the order in which they were added to the
   * container. This method may return the original list unchanged, the original list modified in
   * place, or a different list.
   *
   * <p>If the order is non-deterministic, as with {@link java.util.HashSet}, this method can return
   * its input unmodified. Provided that the test suite is built without {@link

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.project;

import java.io.File;
import java.util.Collections;
import java.util.List;

import org.apache.maven.model.building.ModelProblem;

/**
 * Collects the output of the project builder.
 *
 * @deprecated use {@code org.apache.maven.api.services.ProjectBuilder} instead
 */

        }

    private
    fun <T : Any?> withParsedKotlinSource(sourceRoots: List<File>, block: (List<KtFile>) -> T) =
        Disposer.newDisposable().use {
            parseKotlinFiles(sourceRoots, emptyList()).let(block)
        }

    private
    fun Disposable.parseKotlinFiles(sourceRoots: List<File>, compilationClasspath: List<File>): List<KtFile> {
        configureKotlinCompilerIoForWindowsSupport()

        if (isNewOrRemoved(member)) {
            return null
        }

        List<String> warnings = []
        List<String> errors = []

        def inspectParametersNullabilityOf = { CtBehavior oldBehavior, CtBehavior newBehavior ->

            List<Boolean> oldParametersNullability = parametersNullabilityOf(oldBehavior)
            List<Boolean> newParametersNullability = parametersNullabilityOf(newBehavior)

    /**
     * Displays the file configuration list page.
     *
     * @return HTML response for the list page
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })
    public HtmlResponse index() {
        return asListHtml();
    }

    /**
     * Displays the file configuration list with pagination.
     *
     * @param pageNumber the page number