{* ../../docs_src/metadata/tutorial002_py310.py hl[3] *}

如果你想完全停用 OpenAPI 綱要，可以設定 `openapi_url=None`，同時也會停用依賴它的文件使用者介面。

## 文件 URL { #docs-urls }

你可以設定內建的兩個文件使用者介面：

* Swagger UI：提供於 `/docs`。
    * 可用 `docs_url` 參數設定其 URL。
    * 設定 `docs_url=None` 可停用。
* ReDoc：提供於 `/redoc`。
    * 可用 `redoc_url` 參數設定其 URL。
    * 設定 `redoc_url=None` 可停用。

例如，將 Swagger UI 提供於 `/documentation`，並停用 ReDoc：

        // present supplied by the user. The rule is that we only allow the execution of one ConfigurationProcessor.
        // If there is more than one then we execute the one supplied by the user, otherwise we execute the
        // default SettingsXmlConfigurationProcessor.
        //

  public void testDeadEventForwarding() {
    GhostCatcher catcher = new GhostCatcher();
    bus.register(catcher);

    // A String -- an event for which no one has registered.
    bus.post(EVENT);

    List<DeadEvent> events = catcher.getEvents();
    assertEquals("One dead event should be delivered.", 1, events.size());
    assertEquals("The dead event should wrap the original event.", EVENT, events.get(0).getEvent());
  }

  public void testDeadEventForwarding() {
    GhostCatcher catcher = new GhostCatcher();
    bus.register(catcher);

    // A String -- an event for which no one has registered.
    bus.post(EVENT);

    List<DeadEvent> events = catcher.getEvents();
    assertEquals("One dead event should be delivered.", 1, events.size());
    assertEquals("The dead event should wrap the original event.", EVENT, events.get(0).getEvent());
  }

```

这表示 `item` 可以是 `int` 或 `str`。

#### 可能为 `None` { #possibly-none }

你可以声明一个值的类型是某种类型（比如 `str`），但它也可能是 `None`。

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

使用 `str | None` 而不是仅仅 `str`，可以让编辑器帮助你发现把值当成总是 `str` 的错误（实际上它也可能是 `None`）。

### 类作为类型 { #classes-as-types }

你也可以把类声明为变量的类型。

In this case, it would be better to get **one extra server** and run some processes on it so that they all have **enough RAM and CPU time**.

   *
   * <ul>
   *   <li>use {@link StringReader} instead of {@link CharSequenceReader}. It is faster since it can
   *       use {@link String#getChars(int, int, char[], int)} instead of copying characters one by
   *       one with {@link CharSequence#charAt(int)}.
   *   <li>use {@link Appendable#append(CharSequence)} in {@link #copyTo(Appendable)} and {@link

  public void testEmptySetLast() {
    assertThrows(NoSuchElementException.class, () -> sortedSet.last());
  }

  @CollectionSize.Require(ONE)
  public void testSingletonSetFirst() {
    assertEquals(a, sortedSet.first());
  }

  @CollectionSize.Require(ONE)
  public void testSingletonSetLast() {
    assertEquals(a, sortedSet.last());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<footer class="main-footer">
	<div class="float-right d-none d-sm-inline-block"></div>
	<la:message key="labels.footer.copyright" />

    /**
     * @throws Exception
     */
    @Test
    public void testContains() throws Exception {
        final Set<String> set = new CaseInsensitiveSet();
        set.add("one");
        assertThat(set.contains("ONE"), is(true));
    }