{
                "type": "missing",
                "loc": ["header", "x-token"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "missing",
                "loc": ["header", "x-key"],
                "msg": "Field required",
                "input": None,
            },
        ]
    }

その追加情報はそのまま出力され、JSON Schemaに追加されます。

## `Field`の追加引数

後述する`Field`、`Path`、`Query`、`Body`などでは、任意の引数を関数に渡すことでJSON Schemaの追加情報を宣言することもできます:

{* ../../docs_src/schema_extra_example/tutorial002.py hl[4,10,11,12,13] *}

/// warning | 注意

これらの追加引数が渡されても、文書化のためのバリデーションは追加されず、注釈だけが追加されることを覚えておいてください。

///

## `Body`の追加引数

追加情報を`Field`に渡すのと同じように、`Path`、`Query`、`Body`などでも同じことができます。

public final class okhttp3/dnsoverhttps/DnsOverHttps : okhttp3/Dns {
	public static final field Companion Lokhttp3/dnsoverhttps/DnsOverHttps$Companion;
	public static final field MAX_RESPONSE_SIZE I
	public final fun client ()Lokhttp3/OkHttpClient;
	public final fun includeIPv6 ()Z
	public fun lookup (Ljava/lang/String;)Ljava/util/List;
	public final fun post ()Z
	public final fun resolvePrivateAddresses ()Z
	public final fun resolvePublicAddresses ()Z

		},
		{
			[]clause.Interface{
				clause.Select{}, clause.From{}, clause.OrderBy{
					Expression: clause.Expr{SQL: "FIELD(id, ?)", Vars: []interface{}{[]int{1, 2, 3}}, WithoutParentheses: true},
				},
			},
			"SELECT * FROM `users` ORDER BY FIELD(id, ?,?,?)",
			[]interface{}{1, 2, 3},
		},
	}

	for idx, result := range results {
		t.Run(fmt.Sprintf("case #%v", idx), func(t *testing.T) {

Подробнее — в конце этой страницы.

///

## Дополнительные аргументы `Field` { #field-additional-arguments }

При использовании `Field()` с моделями Pydantic вы также можете объявлять дополнительные `examples`:

{* ../../docs_src/schema_extra_example/tutorial002_py310.py hl[2,8:11] *}

            {
                "type": "missing",
                "loc": ["body", "grant_type"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "missing",
                "loc": ["body", "username"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "missing",

            {
                "type": "missing",
                "loc": ["body", "grant_type"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "missing",
                "loc": ["body", "username"],
                "msg": "Field required",
                "input": None,
            },
            {
                "type": "missing",

from typing import Annotated, Optional

import pytest
from fastapi import FastAPI, Header
from fastapi.testclient import TestClient
from pydantic import BaseModel, Field

app = FastAPI()

# =====================================================================================
# Without aliases


@app.get("/optional-list-str")
async def read_optional_list_str(
    p: Annotated[Optional[list[str]], Header()] = None,
):

	return t.set
}

// MarshalXML encodes transition field into an XML form.
func (t Transition) MarshalXML(enc *xml.Encoder, start xml.StartElement) error {
	if !t.set {
		return nil
	}
	type transitionWrapper Transition
	return enc.EncodeElement(transitionWrapper(t), start)
}

// UnmarshalXML decodes transition field from the XML form.

   * next} field is lazily initialized. The type of that field would be {@code @Nullable T}, and the
   * code would be responsible for populating a "real" {@code T} (which might still be the value
   * {@code null}!) before returning it to callers. Depending on how the code is structured, a
   * nullness analysis might not understand that the field has been populated. To avoid that problem