field.key_field,  # type: ignore[attr-defined]
            cloned_types=cloned_types,
        )
    new_field.validators = field.validators  # type: ignore[attr-defined]
    new_field.pre_validators = field.pre_validators  # type: ignore[attr-defined]
    new_field.post_validators = field.post_validators  # type: ignore[attr-defined]
    new_field.parse_json = field.parse_json  # type: ignore[attr-defined]

    Extra keys passed to `Field` will also be present in the resulting OpenAPI schema for your application.
    As these keys may not necessarily be part of the OpenAPI specification, some OpenAPI tools, for example [the OpenAPI validator](https://validator.swagger.io/), may not work with your generated schema.

## Recap

You can use Pydantic's `Field` to declare extra validations and metadata for model attributes.

    field_info = FieldInfo(annotation=str)
    field = ModelField(name="foo", field_info=field_info)
    assert field.default is Undefined


@needs_pydanticv1
def test_upload_file_dummy_with_info_plain_validator_function():
    # For coverage
    assert UploadFile.__get_pydantic_core_schema__(str, lambda x: None) == {}


@needs_pydanticv1
def test_union_scalar_list():
    # For coverage

    {!> ../../../docs_src/response_model/tutorial002.py!}
    ```

!!! info
    To use `EmailStr`, first install <a href="https://github.com/JoshData/python-email-validator" class="external-link" target="_blank">`email_validator`</a>.

    E.g. `pip install email-validator`
    or `pip install pydantic[email]`.

And we are using this model to declare our input and the same model to declare our output:

=== "Python 3.10+"

    "python-multipart >=0.0.7",
    # For UJSONResponse
    "ujson >=4.0.1,!=4.0.2,!=4.1.0,!=4.2.0,!=4.3.0,!=5.0.0,!=5.1.0",
    # For ORJSONResponse
    "orjson >=3.2.1",
    # To validate email fields
    "email_validator >=2.0.0",
    # Uvicorn with uvloop
    "uvicorn[standard] >=0.12.0",
    # TODO: this should be part of some pydantic optional extra dependencies
    # # Settings management

여러분이 예제를 선언할 때 나중에 이 공식 문서에서 별도 정보를 추가하는 방법을 배울 것입니다.

!!! warning "경고"
    별도 키가 전달된 `Field` 또한 여러분의 어플리케이션의 OpenAPI 스키마에 나타날 것입니다.
    이런 키가 OpenAPI 명세서, [the OpenAPI validator](https://validator.swagger.io/)같은 몇몇 OpenAPI 도구들에 포함되지 못할 수 있으며, 여러분이 생성한 스키마와 호환되지 않을 수 있습니다.

## 요약

모델 어트리뷰트를 위한 추가 검증과 메타데이터 선언하기 위해 Pydantic의 `Field` 를 사용할 수 있습니다.

def get_client():
    from pydantic import BaseModel, ValidationInfo, field_validator

    app = FastAPI()

    class ModelB(BaseModel):
        username: str

    class ModelC(ModelB):
        password: str

    class ModelA(BaseModel):
        name: str
        description: Optional[str] = None
        foo: ModelB

        @field_validator("name")
        def lower_username(cls, name: str, info: ValidationInfo):

        @classmethod
        def __get_validators__(cls) -> Iterable[Callable[..., Any]]:
            yield cls.validate

        @classmethod
        def validate(cls, v: Any) -> str:
            logger.warning(
                "email-validator not installed, email fields will be treated as str.\n"
                "To install, run: pip install email-validator"
            )
            return str(v)

## Opcjonalne zależności

Używane przez Pydantic:

* <a href="https://github.com/JoshData/python-email-validator" target="_blank"><code>email_validator</code></a> - dla walidacji adresów email.

Używane przez Starlette:

* <a href="https://www.python-httpx.org" target="_blank"><code>httpx</code></a> - Wymagane jeżeli chcesz korzystać z `TestClient`.

## Необязательные зависимости

Используется Pydantic:

* <a href="https://github.com/JoshData/python-email-validator" target="_blank"><code>email_validator</code></a> - для проверки электронной почты.

Используется Starlette: