`Query`, `Path`, and other classes you will see later are subclasses of a common `Param` class.

All of them share the same parameters for additional validation and metadata you have seen.

///

/// note | Technical Details

When you import `Query`, `Path` and others from `fastapi`, they are actually functions.

That when called, return instances of classes of the same name.

////

## Tabs and colored boxes { #tabs-and-colored-boxes }

//// tab | Test

/// info
Some text
///

/// note
Some text
///

/// note | Technical details
Some text
///

/// check
Some text
///

/// tip
Some text
///

/// warning
Some text
///

/// danger
Some text
///

////

To do this, use `yield` instead of `return`, and write the extra steps (code) after.

/// tip

Make sure to use `yield` one single time per dependency.

///

/// note | Technical Details

Any function that is valid to use with:

* <a href="https://docs.python.org/3/library/contextlib.html#contextlib.contextmanager" class="external-link" target="_blank">`@contextlib.contextmanager`</a> or

De qualquer forma, em ambos os casos acima, FastAPI irá trabalhar assincronamente e ser extremamente rápido.

Mas, seguindo os passos acima, ele será capaz de fazer algumas otimizações de performance.

## Detalhes Técnicos { #technical-details }

Versões modernas de Python têm suporte para **"código assíncrono"** usando algo chamado **"corrotinas"**, com sintaxe **`async` e `await`**.

Vamos ver aquela frase por partes nas seções abaixo:

Por causa disso, agora é recomendado usar o `lifespan`, como explicado acima.

## Detalhes técnicos { #technical-details }

Apenas um detalhe técnico para nerds curiosos. 🤓

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Assists in resolving the dependencies of a plugin. <strong>Warning:</strong> This is an internal utility class that
 * is only public for technical reasons, it is not part of the public API. In particular, this class can be changed or
 * deleted without prior notice.
 *
 * @since 3.0
 */
@Named
@Singleton

E então outra tarefa em segundo plano gerada na *função de operação de rota* escreverá uma mensagem usando o parâmetro de path `email`.

## Detalhes técnicos { #technical-details }

A classe `BackgroundTasks` vem diretamente de <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">`starlette.background`</a>.

  specific language governing permissions and limitations
  under the License.
-->

<!--
  | Improvements:
  |
  | o add specification element to a field, this would be more a technical description of
  |   what is allowed in the field.
  |
  | o validators: there could be several levels of validation. Simple type validation could

import org.eclipse.aether.metadata.MergeableMetadata;
import org.eclipse.aether.metadata.Metadata;

/**
 * <strong>Warning:</strong> This is an internal utility class that is only public for technical reasons, it is not part
 * of the public API. In particular, this class can be changed or deleted without prior notice.
 *
 */
@Deprecated

        DefaultRepositorySystemSession session = new DefaultRepositorySystemSession(h -> false); // no close handle

        // for technical reasons we cannot throw here, even if delegate does cancel transfer
        listener.transferInitiated(event(session, resource, TransferEvent.EventType.INITIATED));