Das ist keine Limitation von **FastAPI**, sondern Teil des HTTP-Protokolls.

///

## Optionaler Datei-Upload

Sie können eine Datei optional machen, indem Sie Standard-Typannotationen verwenden und den Defaultwert auf `None` setzen:

//// tab | Python 3.10+

```Python hl_lines="9  17"

    id: build-scan-url
    attributes:
      label: Build scan URL (optional)
      description: |
        You can run your build command with `--scan` to publish a Build Scan to [scans.gradle.com](https://scans.gradle.com/).
    validations:
      required: false
  - type: textarea
    id: environment
    attributes:
      label: Your Environment (optional)
      description: |

#### Possibly `None` (Optional)

Ви можете оголосити, що значення може мати тип, наприклад `str`, але також може бути `None`.

У Python 3.6 і вище (включаючи Python 3.10) ви можете оголосити його, імпортувавши та використовуючи `Optional` з модуля `typing`.

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

			Type:        "number",
			Description: `set the number of transition workers` + defaultHelpPostfix(transitionWorkers),
			Optional:    true,
		},
		config.HelpKV{
			Key:         expirationWorkers,
			Type:        "number",
			Description: `set the number of expiration workers` + defaultHelpPostfix(expirationWorkers),
			Optional:    true,
		},
	}

        stablePublicInterface = instanceScopedPool.get(StablePublicInterface.name)

        apiClass.changeStatus >> JApiChangeStatus.MODIFIED
        apiClass.oldClass >> Optional.of(oldBase)
        apiClass.newClass >> Optional.of(newBase)

        internalInterface.name = replaceAsInternal(internalInterface.name)

        interfaces = ['internal': internalInterface,

from dataclasses import dataclass
from datetime import datetime
from typing import List, Optional

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()


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


@app.get("/items/valid", response_model=Item)
def get_valid():

from typing import Dict, List, Optional

from fastapi import FastAPI
from pydantic import BaseModel, Field
from starlette.testclient import TestClient

app = FastAPI()


class Item(BaseModel):
    name: str = Field(alias="aliased_name")
    price: Optional[float] = None
    owner_ids: Optional[List[int]] = None


@app.get("/items/valid", response_model=Item)
def get_valid():
    return Item(aliased_name="valid", price=1.0)

	expireYaml := `
expire: # Expire objects that match a condition
  apiVersion: v1
  bucket: mybucket # Bucket where this batch job will expire matching objects from
  prefix: myprefix # (Optional) Prefix under which this job will expire objects matching the rules below.
  rules:
    - type: object  # regular objects with zero or more older versions
      name: NAME # match object names that satisfy the wildcard expression.

from typing import Optional, Union

from dirty_equals import IsDict
from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class OtherItem(BaseModel):
    price: int


@app.post("/items/")
def save_union_body(item: Union[OtherItem, Item]):
    return {"item": item}

from typing import Optional


def say_hi(name: Optional[str] = None):
    if name is not None:
        print(f"Hey {name}!")
    else: