}

  // Helper to assert common properties of xml escapers.
  static void assertBasicXmlEscaper(
      CharEscaper xmlEscaper, boolean shouldEscapeQuotes, boolean shouldEscapeWhitespaceChars) {
    // Simple examples (smoke tests)
    assertEquals("xxx", xmlEscaper.escape("xxx"));
    assertEquals("test & test & test", xmlEscaper.escape("test & test & test"));
    assertEquals("test &lt;&lt; 1", xmlEscaper.escape("test << 1"));

 * Each implementation must be registered in a {@code META-INF/services/} file corresponding
 * to the specific provider interface being implemented.
 * <p>
 * Example implementation for a custom language provider:
 * <pre>
 * public class CustomLanguageProvider implements LanguageProvider {
 *     public Collection&lt;Language&gt; provides() {
 *         return Arrays.asList(

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

{* ../../docs_src/query_param_models/tutorial002_an_py310.py hl[10] *}

如果客戶端嘗試在**查詢參數**中發送一些**額外的**資料，他們將會收到一個**錯誤**回應。

例如，如果客戶端嘗試發送一個值為 `plumbus` 的 `tool` 查詢參數，如：

```http
https://example.com/items/?limit=10&tool=plumbus
```

他們將收到一個**錯誤**回應，告訴他們查詢參數 `tool` 是不允許的：

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["query", "tool"],

		}
	}
	return time.Time{}, ErrMalformedDate
}

var httpTimeFormats = []string{
	// Do not change this order, http time format dates
	// are usually in http.TimeFormat however there are
	// situations where for example aws-sdk-java doesn't
	// send the correct format.
	http.TimeFormat,
	"Mon, 2 Jan 2006 15:04:05 GMT",
}

// ParseHeader parses http.TimeFormat with an acceptable

    /**
     * Returns a {@link CopyOptions} with the specified delimiter for JavaBeans.
     * <p>
     * When copying between JavaBeans and {@link Map}, you can change the delimiter for property names.
     * For example, if you specify an underscore as the delimiter for JavaBeans and a period as the delimiter for {@link Map},
     * the property names for the source and destination will be as follows:
     * </p>
     * <table border="1">

 * overridden as desired.
 *
 * <p>Usage example:
 *
 * {@snippet :
 * CacheLoader<Key, Graph> loader = new CacheLoader<Key, Graph>() {
 *   public Graph load(Key key) throws AnyException {
 *     return createExpensiveGraph(key);
 *   }
 * };
 * LoadingCache<Key, Graph> cache = CacheBuilder.newBuilder().build(loader);
 * }
 *

                root = root.toLowerCase();

                /* The link entries contain maps of referrals by path representing DFS links.
                 * Note that paths are relative to the root like "\" and not "\example.com\root".
                 */
                CacheEntry links = (CacheEntry) roots.get(root);
                if (links != null && now > links.expiration) {
                    roots.remove(root);

### A response resultante { #the-resulting-response }

Se o cliente faz uma requisição para `http://example.com/items/foo` (um `item_id` `"foo"`), esse cliente receberá um HTTP status code 200, e uma resposta JSON:


```JSON
{
  "item": "The Foo Wrestlers"
}
```

{* ../../docs_src/path_params/tutorial001_py39.py hl[6:7] *}

The value of the path parameter `item_id` will be passed to your function as the argument `item_id`.

So, if you run this example and go to <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, you will see a response of:

```JSON
{"item_id":"foo"}
```