"price": 35.4,
                        "tax": 3.2,
                    },
                },
                "converted": {
                    "summary": "An example with converted data",
                    "description": "FastAPI can convert price `strings` to actual `numbers` automatically",
                    "value": {
                        "name": "Bar",

   *       the same.
   *   <li>The special characters ".", "-", "*", and "_" remain the same.
   *   <li>The space character " " is converted into a plus sign "+".
   *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each
   *       byte is then represented by the 3-character string "%XY", where "XY" is the two-digit,

   *       the same.
   *   <li>The special characters ".", "-", "*", and "_" remain the same.
   *   <li>The space character " " is converted into a plus sign "+".
   *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each
   *       byte is then represented by the 3-character string "%XY", where "XY" is the two-digit,

It would also mean that if you get data from the `Request` object directly (for example, read the body) it won't be validated, converted or documented (with OpenAPI, for the automatic API user interface) by FastAPI.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

     * Returns the OS full name as reported by the system property "os.name".
     * The value is converted to lowercase for consistency.
     *
     * @return the operating system name (never null)
     */
    @Nonnull
    String name();

    /**
     * Returns the OS architecture as reported by the system property "os.arch".
     * The value is converted to lowercase for consistency.
     *

                        "price": 35.4,
                        "tax": 3.2,
                    },
                },
                "converted": {
                    "summary": "An example with converted data",
                    "description": "FastAPI can convert price `strings` to actual `numbers` automatically",
                    "value": {
                        "name": "Bar",

                    "description": "A very nice Item",
                    "price": 35.4,
                    "tax": 3.2,
                },
            },
            "converted": {
                "summary": "An example with converted data",
                "description": "FastAPI can convert price `strings` to actual `numbers` automatically",
                "value": {
                    "name": "Bar",

@needs_py310
def test_typing():
    types = {
        list[int]: [1, 2, 3],
        dict[str, list[int]]: {"a": [1, 2, 3], "b": [4, 5, 6]},
        set[int]: [1, 2, 3],  # `set` is converted to `list`
        tuple[int, ...]: [1, 2, 3],  # `tuple` is converted to `list`
    }
    for test_type, expect in types.items():
        app = FastAPI()

        @app.post("/", response_model=test_type)
        def post_endpoint(input: test_type):

     */
    public static final ArtifactStatus GENERATED = new ArtifactStatus("generated", 1);

    /**
     * Low trust - was converted from the Maven 1.x repository.
     */
    public static final ArtifactStatus CONVERTED = new ArtifactStatus("converted", 2);

    /**
     * Moderate trust - it was deployed directly from a partner.
     */

Así que, incluso con el código anterior que no usa Pydantic explícitamente, FastAPI está usando Pydantic para convertir esos dataclasses estándar en su propia versión de dataclasses de Pydantic.

Y por supuesto, soporta lo mismo:

* validación de datos
* serialización de datos
* documentación de datos, etc.