and not is_union_of_base_models(first_field.type_)
    ):
        return True
    return False


async def _extract_form_body(
    body_fields: list[ModelField],
    received_body: FormData,
) -> dict[str, Any]:
    values = {}

    for field in body_fields:
        value = _get_multidict_value(field, received_body)
        field_info = field.field_info
        if (

def get_openapi_operation_request_body(
    *,
    body_field: Optional[ModelField],
    model_name_map: ModelNameMap,
    field_mapping: dict[
        tuple[ModelField, Literal["validation", "serialization"]], dict[str, Any]
    ],
    separate_input_output_schemas: bool = True,
) -> Optional[dict[str, Any]]:
    if not body_field:
        return None
    assert isinstance(body_field, ModelField)