* receiving. With duplex the request and response may be interleaved! That is, request body bytes
   * may be sent after response headers or body bytes have been received.
   *
   * Though any call may be initiated as a duplex call, only web servers that are specially
   * designed for this nonstandard interaction will use it. As of 2019-01, the only widely-used
   * implementation of this pattern is [gRPC][grpc].
   *

 * introduced in Unicode 3.1. One implication of this is that it rejects <a
 * href="http://www.unicode.org/versions/corrigendum1.html">"non-shortest form"</a> byte sequences,
 * even though the JDK decoder may accept them.
 *
 * @author Martin Buchholz
 * @author Clément Roux
 * @since 16.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Utf8 {
  /**

    // that simply loops through the subscribers and dispatches the event to each would actually
    // probably provide a stronger order guarantee, though that order would obviously be different
    // in some cases.

    /** Global event queue. */
    private final ConcurrentLinkedQueue<EventWithSubscriber> queue =
        Queues.newConcurrentLinkedQueue();

     * Returns true if this ACE is an inherited ACE and false if it is a direct ACE.
     * <p>
     * Note: For reasons not fully understood, <tt>FLAGS_INHERITED</tt> may
     * not be set within all security descriptors even though the ACE was in
     * face inherited. If an inherited ACE is added to a parent the Windows
     * ACL editor will rebuild all children ACEs and set this flag accordingly.
     * 

                /*
                 * This still isn't quite right. If one npa object does not have external
                 * hashes and the other does then they will not be considered equal even
                 * though they may be.
                 */
            }
            return true;
        }
        return false;
    }


    /**
     * @return whether the hashes are externally supplied
     */

 * <tr><td width="20%"><pre>
 * new SmbNamedPipe( "smb1://server/IPC$/foo",
 *         SmbNamedPipe.PIPE_TYPE_RDWR );
 * </pre></td><td>
 * Open the Named Pipe foo for reading and writing. The pipe will
 * behave as though the <code>CreateFile</code>, <code>ReadFile</code>,
 * <code>WriteFile</code>, and <code>CloseFile</code> interface was
 * being used.
 * </td></tr>
 * </table>
 *

<img src="/img/tutorial/metadata/image02.png">

### Order of tags

The order of each tag metadata dictionary also defines the order shown in the docs UI.

For example, even though `users` would go after `items` in alphabetical order, it is shown before them, because we added their metadata as the first dictionary in the list.

## OpenAPI URL

By default, the OpenAPI schema is served at `/openapi.json`.

The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

///

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated`

To achieve that, first import:

* `Query` from `fastapi`

   * href="https://url.spec.whatwg.org/#syntax-url-path-segment">URL path segments</a>. The returned
   * escaper escapes all non-ASCII characters, even though <a
   * href="https://url.spec.whatwg.org/#url-code-points">many of these are accepted in modern
   * URLs</a>. (<a href="https://url.spec.whatwg.org/#path-state">If the escaper were to leave these

{!> ../../docs_src/body_nested_models/tutorial009.py!}
```

////

/// tip

Keep in mind that JSON only supports `str` as keys.

But Pydantic has automatic data conversion.

This means that, even though your API clients can only send strings as keys, as long as those strings contain pure integers, Pydantic will convert them and validate them.

And the `dict` you receive as `weights` will actually have `int` keys and `float` values.