/// note | "Hinweis"

from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: set[str] = set()


@app.post("/items/", response_model=Item, summary="Create an item")
async def create_item(item: Item):
    """
    Create an item with all the information:

from typing import List, Union

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class Hero(SQLModel, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)
    secret_name: str


sqlite_file_name = "database.db"

Le paramètre de requête `q` a pour type `Union[str, None]` (ou `str | None` en Python 3.10), signifiant qu'il est de type `str` mais pourrait aussi être égal à `None`, et bien sûr, la valeur par défaut est `None`, donc **FastAPI** saura qu'il n'est pas requis.

/// note

**FastAPI** saura que la valeur de `q` n'est pas requise grâce à la valeur par défaut `= None`.

            case RepositoryPolicy.CHECKSUM_POLICY_WARN:
                return RepositoryPolicy.CHECKSUM_POLICY_WARN;
            default:
                throw new IllegalArgumentException("unknown repository checksum policy: " + artifactRepositoryPolicy);
        }
    }

	{err: errObjectTampered, errCode: ErrObjectTampered},

	{err: nil, errCode: ErrNone},
	{err: errors.New("Custom error"), errCode: ErrInternalError}, // Case where err type is unknown.
}

func TestAPIErrCode(t *testing.T) {
	ctx := context.Background()
	for i, testCase := range toAPIErrorTests {
		errCode := toAPIErrorCode(ctx, testCase.err)
		if errCode != testCase.errCode {

```

////

## `Union` или `anyOf`

Вы можете определить ответ как `Union` из двух типов. Это означает, что ответ должен соответствовать одному из них.

Он будет определён в OpenAPI как `anyOf`.

Для этого используйте стандартные аннотации типов в Python <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note | "Примечание"

```

////

## `Union` ou `anyOf`

Você pode declarar uma resposta como o `Union` de dois tipos, o que significa que a resposta seria qualquer um dos dois.

Isso será definido no OpenAPI com `anyOf`.

Para fazer isso, use a dica de tipo padrão do Python <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note

from typing import List, Union

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select
from typing_extensions import Annotated


class Hero(SQLModel, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)
    secret_name: str

        @app.get("/query_example/")
        def query_example(
            data: Union[str, None] = Query(
                default=None,
                example="query1",
            ),
        ):
            return data

    @app.get("/query_examples/")
    def query_examples(
        data: Union[str, None] = Query(
            default=None,
            examples=["query1", "query2"],
        ),