Tout comme pour la déclaration de paramètres de requête, quand un attribut de modèle a une valeur par défaut, il n'est pas nécessaire. Sinon, cet attribut doit être renseigné dans le corps de la requête. Pour rendre ce champ optionnel simplement, utilisez `None` comme valeur par défaut.

Par exemple, le modèle ci-dessus déclare un "objet" JSON (ou `dict` Python) tel que :

```JSON
{
    "name": "Foo",

                                    <div class="btn-group">
                                        <la:link href="/admin/dict"
                                                 styleClass="btn btn-default btn-xs">
                                            <em class="fa fa-book">
                                            <la:message key="labels.dict_list_link"/>
                                        </la:link>

                                t = x = i = 0;
                                state = ST_START;
                            }
                            x = 0;
                            break;
                        default:
                            buf[x++] = ch;
                    }
                    break;
            }
        }
        return def;
    }

// Free-version will be added if fi.VersionID has transitioned.
func (x *xlMetaV2) AddFreeVersion(fi FileInfo) error {
	var uv uuid.UUID
	var err error
	switch fi.VersionID {
	case "", nullVersionID:
	default:
		uv, err = uuid.Parse(fi.VersionID)
		if err != nil {
			return err
		}
	}

	for i, version := range x.versions {
		if version.header.VersionID != uv || version.header.Type != ObjectType {
			continue

<div class="termy">

```console
$ pip install "fastapi[standard]"

---> 100%
```

</div>

/// note

When you install with `pip install "fastapi[standard]"` it comes with some default optional standard dependencies.

If you don't want to have those optional dependencies, you can instead install `pip install fastapi`.

///

## Advanced User Guide

  private static final int DEFAULT_VALUES_PER_KEY = 2;

  @VisibleForTesting transient int expectedValuesPerKey = DEFAULT_VALUES_PER_KEY;

  /**
   * Creates a new, empty {@code HashMultimap} with the default initial capacities.
   *
   * <p>You may also consider the equivalent {@code
   * MultimapBuilder.hashKeys().hashSetValues().build()}, which provides more control over the
   * underlying data structure.
   */

        public AttributedStyle style;
        public LineReader reader;
        public ConsolePrompt prompt;

        public void addInHeader(String text) {
            addInHeader(AttributedStyle.DEFAULT, text);
        }

        public void addInHeader(AttributedStyle style, String text) {
            AttributedStringBuilder asb = new AttributedStringBuilder();
            asb.style(style).append(text);

	ps.RLock()
	defer ps.RUnlock()
	for _, sub := range ps.subs {
		if sub.types.Contains(Mask(item.Mask())) && (sub.filter == nil || sub.filter(item)) {
			select {
			case sub.ch <- item:
			default:
			}
		}
	}
}

// Subscribe - Adds a subscriber to pubsub system
func (ps *PubSub[T, M]) Subscribe(mask M, subCh chan T, doneCh <-chan struct{}, filter func(entry T) bool) error {

 
## Changes by Kind

### Deprecation

In both cases, it will have:

* An optional `q` query parameter that is a `str`.
* A `skip` query parameter that is an `int`, with a default of `0`.
* A `limit` query parameter that is an `int`, with a default of `100`.

In both cases the data will be converted, validated, documented on the OpenAPI schema, etc.

## Use it

Now you can declare your dependency using this class.