**FastAPI** allows you to declare additional information and validation for your parameters.

Let's take this application as example:

{* ../../docs_src/query_params_str_validations/tutorial001_py310.py hl[7] *}

The query parameter `q` is of type `str | None`, that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.

/// note

from fastapi.testclient import TestClient

from tests.utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial002_py39"),
        pytest.param("tutorial002_py310", marks=needs_py310),
        pytest.param("tutorial002_an_py39"),
        pytest.param("tutorial002_an_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial011_py39"),
        pytest.param("tutorial011_py310", marks=needs_py310),
        pytest.param("tutorial011_an_py39"),
        pytest.param("tutorial011_an_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):

{* ../../docs_src/custom_request_and_route/tutorial003_py310.py hl[26] *}

En este ejemplo, las *path operations* bajo el `router` usarán la clase personalizada `TimedRoute`, y tendrán un header `X-Response-Time` extra en el response con el tiempo que tomó generar el response:

from inline_snapshot import snapshot

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial004_py39"),
        pytest.param("tutorial004_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.response_model.{request.param}")

    client = TestClient(mod.app)
    return client

import pytest
from fastapi.testclient import TestClient

from tests.utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial003_py39"),
        pytest.param("tutorial003_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.custom_request_and_route.{request.param}")

    client = TestClient(mod.app)

from unittest.mock import patch

import pytest

from ...utils import needs_py310


@pytest.fixture(
    name="module",
    params=[
        pytest.param("tutorial009_py39"),
        pytest.param("tutorial009_py310", marks=needs_py310),
        pytest.param("tutorial009b_py39"),
    ],
)
def get_module(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.python_types.{request.param}")
    return mod

This part is pretty normal, most of the code is probably already familiar to you:

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[7:11,34:51] *}

/// tip

The `callback_url` query parameter uses a Pydantic <a href="https://docs.pydantic.dev/latest/api/networks/" class="external-link" target="_blank">Url</a> type.

///

Essa parte é bastante normal, a maior parte do código provavelmente já é familiar para você:

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[7:11,34:51] *}

/// tip | Dica

O parâmetro de consulta `callback_url` usa um tipo Pydantic <a href="https://docs.pydantic.dev/latest/api/networks/" class="external-link" target="_blank">Url</a>.

///

여기 이를 위한 몇가지 방식이 있습니다.

## Pydantic 모델 속 추가 JSON 스키마 데이터

생성된 JSON 스키마에 추가될 Pydantic 모델을 위한 `examples`을 선언할 수 있습니다.

//// tab | Pydantic v2

{* ../../docs_src/schema_extra_example/tutorial001_py310.py hl[13:24] *}

////

//// tab | Pydantic v1

{* ../../docs_src/schema_extra_example/tutorial001_pv1_py310.py hl[13:23] *}

////

추가 정보는 있는 그대로 해당 모델의 **JSON 스키마** 결과에 추가되고, API 문서에서 사용합니다.