FastAPI will know that the value of `q` is not required because of the default value `= None`.

Having `str | None` will allow your editor to give you better support and detect errors.

///

## Additional validation { #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` { #import-query-and-annotated }

     * This method parses the query string, processes it, and applies any additional customizations.
     *
     * @param queryContext the query context containing the query string
     * @param context a consumer for additional query context customization
     * @throws InvalidQueryException if the query string cannot be parsed
     */

        writeShort(256) // flags with recursion
        writeShort(1) // question count
        writeShort(0) // answerCount
        writeShort(0) // authorityResourceCount
        writeShort(0) // additional

        val nameBuf = Buffer()
        val labels = host.split('.').dropLastWhile { it.isEmpty() }
        for (label in labels) {
          val utf8ByteCount = label.utf8Size()

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

          or as an addendum to the NOTICE text from the Work, provided
          that such additional attribution notices cannot be construed
          as modifying the License.

      You may add Your own copyright statement to Your modifications and
      may provide additional or different license terms and conditions
      for use, reproduction, or distribution of Your modifications, or

Sie wird nicht in der Dokumentation angezeigt, aber andere Tools (wie z. B. Sphinx) können den Rest verwenden.

{* ../../docs_src/path_operation_advanced_configuration/tutorial004_py310.py hl[17:27] *}

## Zusätzliche Responses { #additional-responses }

Sie haben wahrscheinlich gesehen, wie man das `response_model` und den `status_code` für eine *Pfadoperation* deklariert.

## Notas { #notes }

Cuando devuelves una `Response` directamente, sus datos no son validados, convertidos (serializados), ni documentados automáticamente.

Pero aún puedes documentarlo como se describe en [Additional Responses in OpenAPI](additional-responses.md){.internal-link target=_blank}.

<?xml version="1.0" encoding="UTF-8"?>

<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at