from datetime import datetime
from typing import Union

from pydantic import BaseModel


class User(BaseModel):
    id: int
    name: str = "John Doe"
    signup_ts: Union[datetime, None] = None
    friends: list[int] = []


external_data = {
    "id": "123",
    "signup_ts": "2017-06-01 12:22",
    "friends": [1, "2", b"3"],
}
user = User(**external_data)
print(user)

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(
        default=None,
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None, Query(min_length=3, max_length=50, pattern="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from fastapi import FastAPI
from fastapi.openapi.docs import (
    get_redoc_html,
    get_swagger_ui_html,
    get_swagger_ui_oauth2_redirect_html,
)

app = FastAPI(docs_url=None, redoc_url=None)


@app.get("/docs", include_in_schema=False)
async def custom_swagger_ui_html():
    return get_swagger_ui_html(
        openapi_url=app.openapi_url,
        title=app.title + " - Swagger UI",

```

////

Em ambos os casos, isso significa que `item` poderia ser um `int` ou um `str`.

#### Possivelmente `None` { #possibly-none }

Você pode declarar que um valor pode ter um tipo, como `str`, mas que ele também pode ser `None`.

No Python 3.6 e superior (incluindo o Python 3.10) você pode declará-lo importando e utilizando `Optional` do módulo `typing`.

```Python hl_lines="1  4"

```

////

En ambos casos, esto significa que `item` podría ser un `int` o un `str`.

#### Posiblemente `None` { #possibly-none }

Puedes declarar que un valor podría tener un tipo, como `str`, pero que también podría ser `None`.

En Python 3.6 y posteriores (incluyendo Python 3.10) puedes declararlo importando y usando `Optional` del módulo `typing`.

```Python hl_lines="1  4"

		expectedCode      int
	}{
		// If-None-Match(false) and If-Modified-Since(true)
		{
			name:            "If-None-Match1",
			ifNoneMatch:     "aa",
			ifModifiedSince: "Sun, 26 Aug 2024 02:01:00 GMT",
			objInfo:         objInfo,
			expectedFlag:    true,
			expectedCode:    304,
		},
		// If-Modified-Since(false)
		{
			name:            "If-None-Match2",
			ifNoneMatch:     "aaa",

from pydantic import BaseModel, WithJsonSchema

app = FastAPI()


class Item(BaseModel):
    name: str

    description: Annotated[
        Optional[str], WithJsonSchema({"type": ["string", "null"]})
    ] = None

    model_config = {
        "json_schema_extra": {
            "x-something-internal": {"level": 4},
        }
    }


@app.get("/foo", response_model=Item)
def foo():
    return {"name": "Foo item"}

from fastapi.testclient import TestClient
from pydantic.dataclasses import dataclass

app = FastAPI()


@dataclass
class Item:
    name: str
    price: Optional[float] = None
    owner_ids: Optional[list[int]] = None


@app.get("/items/invalid", response_model=Item)
def get_invalid():
    return {"name": "invalid", "price": "foo"}


@app.get("/items/innerinvalid", response_model=Item)

      checkNotDone();
      checkNotNull(bytes);
      mac.update(bytes);
    }

    private void checkNotDone() {
      checkState(!done, "Cannot re-use a Hasher after calling hash() on it");
    }

    @Override
    public HashCode hash() {
      checkNotDone();
      done = true;
      return HashCode.fromBytesNoCopy(mac.doFinal());
    }
  }