from typing import List, Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: List[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},

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, alias="item-query")):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

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,
        alias="item-query",
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
        max_length=50,
        pattern="^fixedquery$",
        deprecated=True,

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


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

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[Union[str, None], Query(title="Query string", min_length=3)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

		case "s": // set
			v, err := strconv.ParseInt(kv[1], 10, 64)
			if err != nil {
				o.ID = mustGetUUID()
				o.Create = true
				continue
			}
			o.set = int(v)
		default:
			// Ignore unknown
		}
	}
}

// encodeMarker will encode a uuid and return it as a marker.
// uuid cannot contain '[', ':' or ','.
func (o listPathOptions) encodeMarker(marker string) string {
	if o.ID == "" {

func getFSType(ftype int32) string {
	fsTypeHex := strconv.FormatInt(int64(ftype), 16)
	fsTypeString, ok := fsType2StringMap[fsTypeHex]
	if !ok {
		return "UNKNOWN"
	}
	return fsTypeString
}

// GetInfo returns total and free bytes available in a directory, e.g. `/`.
func GetInfo(path string, _ bool) (info Info, err error) {
	s := syscall.Statfs_t{}

  // the tensor handle can be an error and return non-OK status.
  virtual absl::Status TensorHandleStatus() const;

  // Returns tensor shape. If tensor has unknown rank, shape remains untouched.
  virtual absl::Status Shape(tensorflow::PartialTensorShape* shape) const = 0;

  // Returns tensor (full) type.
  // While there is no immediate plan to deprecate dtype and shape in favor

```

////

#### Utilizando `Union` ou `Optional`

Se você está utilizando uma versão do Python abaixo da 3.10, aqui vai uma dica do meu ponto de vista bem **subjetivo**:

* 🚨 Evite utilizar `Optional[SomeType]`
* No lugar, ✨ **use `Union[SomeType, None]`** ✨.

from typing import Union

from fastapi import FastAPI
from fastapi.responses import FileResponse
from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


responses = {
    404: {"description": "Item not found"},
    302: {"description": "The item was moved"},
    403: {"description": "Not enough privileges"},
}


app = FastAPI()


@app.get(
    "/items/{item_id}",