* Subclasses should override one or more methods to modify the behavior of the backing multimap as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations

 * override one or more methods to modify the behavior of the backing map as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class forwards calls to <i>only some</i> {@code
 * default} methods. Specifically, it forwards calls only for methods that existed <a

 * Subclasses should override one or more methods to modify the behavior of the backing deque as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingBlockingDeque} forward <b>indiscriminately</b>
 * to the methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change

#### Определите *декоратор операции пути (path operation decorator)*

```Python hl_lines="6"
{!../../docs_src/first_steps/tutorial001.py!}
```

Декоратор `@app.get("/")` указывает **FastAPI**, что функция, прямо под ним, отвечает за обработку запросов, поступающих по адресу:

* путь `/`
* использующих <abbr title="HTTP GET метод"><code>get</code> операцию</abbr>

/// info | "`@decorator` Дополнительная информация"

 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p>Note that {@link #get}, {@link #getUnchecked}, and {@link #apply} all expose the same
 * underlying functionality, so should probably be overridden as a group.
 *
 * @author Charles Fry

 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p>Note that {@link #get}, {@link #getUnchecked}, and {@link #apply} all expose the same
 * underlying functionality, so should probably be overridden as a group.
 *
 * @author Charles Fry

///

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

## Documenting the callback

The actual callback code will depend heavily on your own API app.

And it will probably vary a lot from one app to the next.

 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations

 * Subclasses should override one or more methods to modify the behavior of the backing multimap as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations

 * should override one or more methods to modify the behavior of the backing future as desired per
 * the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p>Most subclasses can just use {@link SimpleForwardingListenableFuture}.
 *
 * @author Shardul Deo
 * @since 4.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault