{* ../../docs_src/extra_models/tutorial002.py hl[9,15,16,19,20,23,24] *}

## `Union`または`anyOf`

レスポンスを２つの型の`Union`として宣言することができます。

OpenAPIでは`anyOf`で定義されます。

そのためには、標準的なPythonの型ヒント<a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>を使用します:

{* ../../docs_src/extra_models/tutorial003.py hl[1,14,15,18,19,20,33] *}

## モデルのリスト

Esse é o benefício dos padrões...

///

## Veja em ação { #see-it-in-action }

Abra o docs interativo: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

### Autentique-se { #authenticate }

Clique no botão "Authorize".

Use as credenciais:

User: `johndoe`

    int iterations = 10;
    WeakReference<Object> ref = new WeakReference<>(null);
    int expectedComputations = 0;
    for (int i = 0; i < iterations; i++) {
      // The entry should get garbage collected and recomputed.
      Object oldValue = ref.get();
      if (oldValue == null) {
        expectedComputations++;
      }
      ref = new WeakReference<>(cache.getUnchecked(1));
      oldValue = null;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Ordering;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.J2ObjCIncompatible;
import java.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

        if (obj == null) {
            enc_ndr_long(0);
            return;
        }
        switch (type) {
        case 1: /* unique */
        case 3: /* ref */
            enc_ndr_long(System.identityHashCode(obj));
            return;
        case 2: /* ptr */
            enc_ndr_long(getDceReferent(obj));
        }
    }

    @Override

/// info

第一个版本是「相对导入」：

```Python
from .routers import items, users
```

第二个版本是「绝对导入」：

```Python
from app.routers import items, users
```

要了解有关 Python 包和模块的更多信息，请查阅<a href="https://docs.python.org/3/tutorial/modules.html" class="external-link" target="_blank">关于 Modules 的 Python 官方文档</a>。

///

### 避免名称冲突

我们将直接导入 `items` 子模块，而不是仅导入其 `router` 变量。

```

그래서 `Query`를 필수값으로 만들어야 할 때면, 첫 번째 인자로 `...`를 사용할 수 있습니다:

{* ../../docs_src/query_params_str_validations/tutorial006.py hl[7] *}

/// info | 정보

이전에 `...`를 본적이 없다면: 특별한 단일값으로, <a href="https://docs.python.org/3/library/constants.html#Ellipsis" class="external-link" target="_blank">파이썬의 일부이며 "Ellipsis"라 부릅니다</a>.

///

이렇게 하면 **FastAPI**가 이 매개변수는 필수임을 알 수 있습니다.

## 쿼리 매개변수 리스트 / 다중값

   * representation to this hash code.
   *
   * <p><b>Security note:</b> this method uses a constant-time (not short-circuiting) implementation
   * to protect against <a href="http://en.wikipedia.org/wiki/Timing_attack">timing attacks</a>.
   */
  @Override
  public final boolean equals(@Nullable Object object) {
    if (object instanceof HashCode) {
      HashCode that = (HashCode) object;

```

### `RequestValidationError` vs `ValidationError`

/// warning | 警告

如果您觉得现在还用不到以下技术细节，可以先跳过下面的内容。

///

`RequestValidationError` 是 Pydantic 的 <a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a> 的子类。

Dessa forma a sessão liberaria a conexão com o banco de dados, para que outras requisições pudessem usá-la.