{* ../../docs_src/header_param_models/tutorial002_an_py310.py hl[10] *}

Si un client essaie d'envoyer des **en-têtes supplémentaires**, il recevra une **réponse d'erreur**.

Par exemple, si le client essaie d'envoyer un en-tête `tool` avec la valeur `plumbus`, il recevra une **réponse d'erreur** lui indiquant que le paramètre d'en-tête `tool` n'est pas autorisé :

```json
{
    "detail": [
        {

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Forbid Extra Headers { #forbid-extra-headers }

In some special use cases (probably not very common), you might want to **restrict** the headers that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

{* ../../docs_src/header_param_models/tutorial002_an_py310.py hl[10] *}

# all those branch names and heads as a conservative snapshot
# of the entire remote repo state, and use that as the tag sum.
# Any change on the server then invalidates the tag sum,
# even if it didn't have anything to do with tags, but at least
# we will avoid re-cloning a server when there have been no
# changes at all.
#
# Separately, this extension also adds a 'golookup' command that

 *
 * <ul>
 *   <li>size: The length of the byte array to hash.
 *   <li>hashFunctionEnum: The {@link HashFunction} to use for hashing.
 * </ul>
 *
 * @author Kurt Alfred Kluever
 */
@NullUnmarked
public class HashFunctionBenchmark {

  // Use a statically configured random instance for all of the benchmarks
  private static final Random random = new Random(42);

 *
 * <ul>
 *   <li>size: The length of the byte array to hash.
 *   <li>hashFunctionEnum: The {@link HashFunction} to use for hashing.
 * </ul>
 *
 * @author Kurt Alfred Kluever
 */
@NullUnmarked
public class HashFunctionBenchmark {

  // Use a statically configured random instance for all of the benchmarks
  private static final Random random = new Random(42);

                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI), check the short tutorial: [Python Types](python-types.md).

You write standard Python with types:

```Python
from datetime import date

from pydantic import BaseModel

/*
 * Copyright (C) 2016 The Guava Authors
 *
 * Licensed 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
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

 * to the provided {@code standardEquals} method.
 *
 * <p>Each of the {@code standard} methods, where appropriate, use {@link Objects#equals} to test
 * equality for both keys and values. This may not be the desired behavior for map implementations
 * that use non-standard notions of key equality, such as the entry of a {@code SortedMap} whose
 * comparator is not consistent with {@code equals}.
 *

  // It's a constant, and we can't use ImmutableMap here without creating a circular dependency.
  @SuppressWarnings("ConstantCaseForConstants")
  private static final Map<Class<?>, Class<?>> PRIMITIVE_TO_WRAPPER_TYPE;

  /** A map from wrapper types to their corresponding primitive types. */
  // It's a constant, and we can't use ImmutableMap here without creating a circular dependency.