### Type Annotations and Tooling { #type-annotations-and-tooling }

First let's see how editors, mypy and other tools would see this.

`BaseUser` has the base fields. Then `UserIn` inherits from `BaseUser` and adds the `password` field, so, it will include all the fields from both models.

We annotate the function return type as `BaseUser`, but we are actually returning a `UserIn` instance.

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">

type ClauseBuilder func(Clause, Builder)

type Writer interface {
	WriteByte(byte) error
	WriteString(string) (int, error)
}

// Builder builder interface
type Builder interface {
	Writer
	WriteQuoted(field interface{})
	AddVar(Writer, ...interface{})
	AddError(error) error
}

// Clause
type Clause struct {
	Name                string // WHERE
	BeforeExpression    Expression
	AfterNameExpression Expression

client = TestClient(app)


def test_get_validation_error():
    response = client.get("/items/foo")
    assert response.status_code == 400, response.text
    assert "Validation errors:" in response.text
    assert "Field: ('path', 'item_id')" in response.text


def test_get_http_error():
    response = client.get("/items/3")
    assert response.status_code == 418, response.text
    assert response.content == b"Nope! I don't like 3."

    with pytest.raises(ValidationError) as exc_info:
        importlib.import_module(mod_name)
    assert exc_info.value.errors() == [
        {
            "loc": ("admin_email",),
            "msg": "Field required",
            "type": "missing",
            "input": {},
            "url": IsAnyStr,
        }
    ]


def test_app(client: TestClient):
    response = client.get("/info")

    assert response.status_code == 422
    assert response.json() == {
        "detail": [
            {
                "type": "missing",
                "loc": ["query", "q"],
                "msg": "Field required",
                "input": None,
            }
        ]
    }


def test_query_params_str_validations_q_fixedquery(client: TestClient):
    response = client.get("/items/", params={"q": "fixedquery"})

그 전에는, 하나의 예제만 가능한 `example` 키워드만 지원했습니다. 이는 아직 OpenAPI 3.1.0에서 지원하지만, 지원이 종료될 것이며 JSON 스키마 표준에 포함되지 않습니다. 그렇기에 `example`을 `examples`으로 이전하는 것을 추천합니다. 🤓

이 문서 끝에 더 많은 읽을거리가 있습니다.

///

## `Field` 추가 인자

Pydantic 모델과 같이 `Field()`를 사용할 때 추가적인 `examples`를 선언할 수 있습니다:

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

## JSON Schema에서의 `examples` - OpenAPI

이들 중에서 사용합니다:

* `Path()`

你可以按如下方式设置它们：

{* ../../docs_src/query_param_models/tutorial001_an_py310.py hl[9:13,17] *}

**FastAPI** will **extract** the data for **each field** from the **query parameters** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the query parameters in the docs UI at `/docs`:

<div class="screenshot">

 * is mapped to an equally named property of the bean and converted. The properties of the bean are supposed to either
 * have a public setter or be backed by an equally named field (of any visibility).
 *
 * @since 3.0
 */
public interface BeanConfigurator {

    /**
     * Performs the specified bean configuration.
     *