*   <li>USER_AGENT_PROPERTY: User agent string.</li>
 *   <li>ROBOTS_TXT_ENABLED_PROPERTY: Enable or disable robots.txt parsing.</li>
 *   <li>AUTHENTICATIONS_PROPERTY: Web authentications.</li>
 *   <li>REQUEST_HEADERS_PROPERTY: Custom request headers.</li>
 *   <li>REDIRECTS_ENABLED: Enable or disable HTTP redirects.</li>
 *   <li>COOKIES_PROPERTY: Cookie settings.</li>
 *   <li>AUTH_SCHEME_PROVIDERS_PROPERTY: Authentication scheme providers.</li>

But you can also provide other alternative `servers`, for example if you want *the same* docs UI to interact with both a staging and a production environment.

If you pass a custom list of `servers` and there's a `root_path` (because your API lives behind a proxy), **FastAPI** will insert a "server" with this `root_path` at the beginning of the list.

For example:

		// the client. So, logger and Error response XML were not using this
		// value. This is set here so that this header can be logged as
		// part of the log entry, Error response XML and auditing.
		// Set custom headers such as x-amz-request-id for each request.
		w.Header().Set(xhttp.AmzRequestID, mustGetRequestID(UTCNow()))
		if globalLocalNodeName != "" {
			w.Header().Set(xhttp.AmzRequestHostID, globalLocalNodeNameHex)
		}

- Alpha support for field selectors on custom resources has been added. With the `CustomResourceFieldSelectors` feature gate enabled, the CustomResourceDefinition API now allows specifying `selectableFields`. Listing a field there enables filtering custom resources for that CustomResourceDefinition in list or watch requests. ([#122717](https://github.com/kubernetes/kubernetes/pull/122717), [@jp...

	// Find
	var toys []Toy
	if DB.Model(&users).Association("Toys").Find(&toys); len(toys) != 6 {
		t.Errorf("toys count should be %v, but got %v", 6, len(toys))
	}

	// Find Tools (polymorphic with custom type and id)
	var tools []Tools
	DB.Model(&users).Association("Tools").Find(&tools)

	if len(tools) != 2 {
		t.Errorf("tools count should be %v, but got %v", 2, len(tools))
	}

	// Append

  @Override
  public Set<Entry<K, V>> entrySet() {
    // does not impact recency ordering
    Set<Entry<K, V>> es = entrySet;
    return (es != null) ? es : (entrySet = new EntrySet(this));
  }

  /**
   * Custom Entry class used by EntryIterator.next(), that relays setValue changes to the underlying
   * map.
   */
  private final class WriteThroughEntry implements Entry<K, V> {
    final K key;
    V value;

    return new ArrayTable<>(rowKeys, columnKeys);
  }

  /*
   * TODO(jlevy): Add factory methods taking an Enum class, instead of an
   * iterable, to specify the allowed row keys and/or column keys. Note that
   * custom serialization logic is needed to support different enum sizes during
   * serialization and deserialization.
   */

  /**
   * Creates an {@code ArrayTable} with the mappings in the provided table.
   *

            queryFieldConfig = new QueryFieldConfig();
            queryFieldConfig.init();
        }
    }

    public void test_init_withAdditionalDefaultFields() {
        // Create custom FessConfig with additional default fields
        FessConfig fessConfig = new FessConfig.SimpleImpl() {

            @Override
            public String getQueryAdditionalDefaultFields() {

     */
    public void setCacheDuration(final long cacheDuration) {
        this.cacheDuration = cacheDuration;
    }

    /**
     * DefaultNamespaceContext is a custom implementation of NamespaceContext.
     * It is used to resolve namespace URIs for XML elements and attributes
     * within the context of the provided XML document node.
     */

```Python hl_lines="30-31" title="app/routers/items.py"
{!../../docs_src/bigger_applications/app/routers/items.py!}
```

/// tip | Consejo

Esta última *path operation* tendrá la combinación de tags: `["items", "custom"]`.

Y también tendrá ambas responses en la documentación, una para `404` y otra para `403`.

///

## El `FastAPI` principal

Ahora, veamos el módulo en `app/main.py`.