```Python hl_lines="1 4"
{!../../../docs_src/python_types/tutorial009.py!}
```

O uso de `Opcional [str]` em vez de apenas `str` permitirá que o editor o ajude a detectar erros, onde você pode estar assumindo que um valor é sempre um `str`, quando na verdade também pode ser `None`.

#### Tipos genéricos

Esses tipos que usam parâmetros de tipo entre colchetes, como:

* `List`
* `Tuple`

from fastapi.dependencies.utils import (
    multipart_incorrect_install_error,
    multipart_not_installed_error,
)


def test_incorrect_multipart_installed_form(monkeypatch):
    monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
    with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
        app = FastAPI()

        @app.post("/")

                """
            ),
        ] = None,
        auto_error: Annotated[
            bool,
            Doc(
                """
                By default, if the query parameter is not provided, `APIKeyQuery` will
                automatically cancel the request and send the client an error.

                If `auto_error` is set to `False`, when the query parameter is not

1 validation error
path -> item_id
  value is not a valid integer (type=type_error.integer)
```

#### `RequestValidationError` vs `ValidationError`

!!! warning
    These are technical details that you might skip if it's not important for you now.

`RequestValidationError` is a sub-class of Pydantic's <a href="https://docs.pydantic.dev/latest/concepts/models/#error-handling" class="external-link" target="_blank">`ValidationError`</a>.

                    "loc": ["body", "file"],
                    "msg": "field required",
                    "type": "value_error.missing",
                },
                {
                    "loc": ["body", "fileb"],
                    "msg": "field required",
                    "type": "value_error.missing",
                },
                {
                    "loc": ["body", "token"],

                    "loc": ["body", 0, "name"],
                    "msg": "field required",
                    "type": "value_error.missing",
                },
                {
                    "loc": ["body", 0, "age"],
                    "msg": "value is not a valid decimal",
                    "type": "type_error.decimal",
                },
                {
                    "loc": ["body", 1, "name"],

        )
        # TODO: remove when deprecating Pydantic v1
        | IsDict(
            {
                "loc": ["query", "foo"],
                "msg": "field required",
                "type": "value_error.missing",
            }
        )
    ]
}
foo_is_short = {
    "detail": [
        IsDict(
            {
                "ctx": {"min_length": 1},
                "loc": ["query", "foo"],

from fastapi.testclient import TestClient

from docs_src.handling_errors.tutorial004 import app

client = TestClient(app)


def test_get_validation_error():
    response = client.get("/items/foo")
    assert response.status_code == 400, response.text
    # TODO: remove when deprecating Pydantic v1
    assert (
        # TODO: remove when deprecating Pydantic v1
        "path -> item_id" in response.text

                    "msg": "value is not a valid integer",
                    "type": "type_error.integer",
                },
                {
                    "loc": ["query", "q", 1],
                    "msg": "value is not a valid integer",
                    "type": "type_error.integer",
                },
            ]
        }
    )


def test_openapi_schema():

        {
            "detail": [
                {
                    "loc": ["body", "item2"],
                    "msg": "field required",
                    "type": "value_error.missing",
                }
            ]
        }
    )


def test_no_duplicates():
    response = client.post(
        "/no-duplicates",