*
     * @return channel statistics
     */
    public ChannelStatistics getStatistics() {
        return new ChannelStatistics(sessionChannels.size(),
                sessionChannels.values().stream().mapToInt(ChannelGroup::getChannelCount).sum(), totalRequests.get(),
                totalChannelsCreated.get());
    }

    /**
     * Channel statistics.
     */

Import `BaseSettings` from Pydantic and create a sub-class, very much like with a Pydantic model.

The same way as with Pydantic models, you declare class attributes with type annotations, and possibly default values.

You can use all the same validation features and tools you use for Pydantic models, like different data types and additional validations with `Field()`.

{* ../../docs_src/settings/tutorial001_py39.py hl[2,5:8,11] *}

                context.unindent();
            }
        }

        return new UpgradeResult(processedPoms, modifiedPoms, errorPoms);
    }

    /**
     * Fixes unsupported combine.children attribute values.
     * Maven 4 only supports 'append' and 'merge', not 'override'.
     */
    private boolean fixUnsupportedCombineChildrenAttributes(Document pomDocument, UpgradeContext context) {
        boolean fixed = false;

            for (Option option : commandLine.getOptions()) {
                if (!CommonsCliOptions.CLIManager.USER_PROPERTY.equals(option.getOpt())) {
                    List<String> values = option.getValuesList();
                    for (ListIterator<String> it = values.listIterator(); it.hasNext(); ) {
                        it.set(interpolator.interpolate(it.next(), callback));
                    }
                }

        String version = metadata.getVersion();
        if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {
            // meta-versions are not valid <version/> values...don't write them.
            metadata.setVersion(null);
        }

        if (changed || !metadataFile.exists()) {
            metadataFile.getParentFile().mkdirs();

                return lx - rx;
            }
        };

        Map<String, Lifecycle> lifecyclesMap = lookupLifecycles();

        // ensure canonical order of standard lifecycles
        return lifecyclesMap.values().stream()
                .peek(l -> Objects.requireNonNull(l.getId(), "A lifecycle must have an id."))
                .sorted(Comparator.comparing(Lifecycle::getId, comparator))
                .collect(Collectors.toList());

* `skip`, um `int` com o valor padrão `0`.
* `limit`, um `int` opcional.

/// tip | Dica

Você também poderia usar `Enum` da mesma forma que com [Path Parameters](path-params.md#predefined-values){.internal-link target=_blank}.

* `skip`, un `int` con un valor por defecto de `0`.
* `limit`, un `int` opcional.

/// tip | Consejo

También podrías usar `Enum`s de la misma manera que con [Parámetros de Path](path-params.md#predefined-values){.internal-link target=_blank}.

Es wird die Validierung dieser zusammengesetzten Daten übernehmen, und diese im OpenAPI-Schema und der automatischen Dokumentation dokumentieren.

## Einzelne Werte im Body { #singular-values-in-body }

So wie `Query` und `Path` für Query- und Pfad-Parameter, stellt **FastAPI** das Äquivalent `Body` zur Verfügung, um Extra-Daten für Body-Parameter zu definieren.

 * invoke methods, they invoke methods on the {@code ForwardingSortedMap}.
 *
 * <p>Each of the {@code standard} methods, where appropriate, use the comparator of the map to test
 * equality for both keys and values, unlike {@code ForwardingMap}.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *