### Install `pydantic-settings` { #install-pydantic-settings }

First, make sure you create your [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install the `pydantic-settings` package:

<div class="termy">

```console

이전 스크린샷은 <a href="https://code.visualstudio.com" class="external-link" target="_blank">Visual Studio Code</a>를 찍은 것입니다.

하지만 똑같은 편집기 지원을 <a href="https://www.jetbrains.com/pycharm/" class="external-link" target="_blank">PyCharm</a>에서 받을 수 있거나, 대부분의 다른 편집기에서도 받을 수 있습니다:

<img src="/img/tutorial/body/image05.png">

/// tip | 팁

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

Isso ainda é suportado graças ao **Pydantic**, pois ele tem <a href="https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">suporte interno para `dataclasses`</a>.

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

Esto sigue siendo soportado gracias a **Pydantic**, ya que tiene <a href="https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">soporte interno para `dataclasses`</a>.

* [Внутренняя ссылка](index.md#installation){.internal-link target=_blank}
* <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">Внешняя ссылка</a>
* <a href="https://fastapi.tiangolo.com/css/styles.css" class="external-link" target="_blank">Ссылка на стиль</a>
* <a href="https://fastapi.tiangolo.com/js/logic.js" class="external-link" target="_blank">Ссылка на скрипт</a>

///

## Anwendungsfälle { #use-cases }

Einige Anwendungsfälle sind:

* Konvertieren von Nicht-JSON-Requestbodys nach JSON (z. B. <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).
* Dekomprimierung gzip-komprimierter Requestbodys.
* Automatisches Loggen aller Requestbodys.

Sie sehen die automatische API-Dokumentation für die Hauptanwendung, welche nur deren eigene _Pfadoperationen_ anzeigt:

<img src="/img/tutorial/sub-applications/image01.png">

Öffnen Sie dann die Dokumentation für die Unteranwendung unter <a href="http://127.0.0.1:8000/subapi/docs" class="external-link" target="_blank">http://127.0.0.1:8000/subapi/docs</a>.

import java.util.WeakHashMap;

/**
 * Represents a parsed phase identifier.
 */
public class PhaseId {
    /**
     * Interned {@link PhaseId} instances.
     */
    private static final Map<String, PhaseId> INSTANCES = new WeakHashMap<>();

    /**
     * The execution point of this {@link PhaseId}.
     */
    private final PhaseExecutionPoint executionPoint;

    /**

import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Tests for {@link ImmutableGraph} and {@link ImmutableGraph.Builder} that are not ready covered by
 * {@link StandardImmutableDirectedGraphTest}.
 */
@RunWith(JUnit4.class)
@NullUnmarked
public class StandardImmutableGraphAdditionalTest {

  @Test
  public void immutableGraph() {

/**
 * Exception thrown when an argument is null.
 *
 * Intended to be used instead of throwing {@link NullPointerException}.
 *
 * @author wyukawa
 */
public class NullArgumentException extends ClIllegalArgumentException {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    /**
     * Creates a {@link NullArgumentException}.
     *
     * @param argName