"paid": true
}
```

and it would expect a response from that *external API* with a JSON body like:

```JSON
{
    "ok": true
}
```

/// tip

Notice how the callback URL used contains the URL received as a query parameter in `callback_url` (`https://www.external.org/events`) and also the invoice `id` from inside of the JSON body (`2expen51ve`).

///

            "name": "The Foo live"
        },
        {
            "url": "http://example.com/dave.jpg",
            "name": "The Baz"
        }
    ]
}
```

/// info

Notice how the `images` key now has a list of image objects.

///

## Deeply nested models

You can define arbitrarily deeply nested models:

//// tab | Python 3.10+

Para isso, você utiliza o `TestClient` dentro de uma instrução `with`, conectando com o WebSocket:

```Python hl_lines="27-31"
{!../../docs_src/app_testing/tutorial002.py!}
```

/// note | "Nota"

Para mais detalhes, confira a documentação do Starlette para <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testar WebSockets</a>.

You can use the same `TestClient` to test WebSockets.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

```Python hl_lines="27-31"
{!../../docs_src/app_testing/tutorial002.py!}
```

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

   *
   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that
   * multiple threads can concurrently load values for distinct keys.
   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values

Note: each component can be installed in parallel with an existing Istio 1.0 or 1.1 installation in
`istio-system`. The new components will not interfere with existing apps, but can interoperate,
and it is possible to gradually move apps from Istio 1.0/1.1 to the new environments and
across environments ( for example canary -> prod )

   *     of this class typically expect for instances to have a non-null cause. At the moment, you
   *     can <i>usually</i> still preserve behavior by passing an explicit {@code null} cause. Note,
   *     however, that passing an explicit {@code null} cause prevents anyone from calling {@link
   *     #initCause} later, so it is not quite equivalent to using a constructor that omits the
   *     cause.
   */

- Changes to Bucket features such as:
  - Bucket Policies
  - Bucket Tags
  - Bucket Object-Lock configurations (including retention and legal hold configuration)
  - Bucket Encryption configuration

> NOTE: Bucket versioning is automatically enabled for all new and existing buckets on all replicated sites.

The following Bucket features will **not be replicated**, is designed to differ between sites:

   * document's character encoding can encode any non-ASCII code points in the input (as UTF-8 and
   * other Unicode encodings can).
   *
   * <p><b>Note:</b> This escaper only performs minimal escaping to make content structurally
   * compatible with HTML. Specifically, it does not perform entity replacement (symbolic or

   * that of <code>((Double) a).{@linkplain Double#compareTo compareTo}(b)</code>. As with that
   * method, {@code NaN} is treated as greater than all other values, and {@code 0.0 > -0.0}.
   *
   * <p><b>Note:</b> this method simply delegates to the JDK method {@link Double#compare}. It is
   * provided for consistency with the other primitive types, whose compare methods were not added
   * to the JDK until JDK 7.
   *