📝 Add docs recommending Union over Optional and migrate source examples (#4908)

* 📝 Add docs recommending Union over Optional

* 📝 Update docs recommending Union over Optional

* 📝 Update source examples for docs, recommend Union over Optional

* 📝 Update highlighted lines with updated source examples

* 📝 Update highlighted lines in Markdown with recent code changes

* 📝 Update docs, use Union instead of Optional

* ♻️ Update source examples to recommend Union over Optional

* 🎨 Update highlighted code in Markdown after moving from Optional to Union

docs_src/additional_responses/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.responses import FileResponse
@@ -23,7 +23,7 @@ app = FastAPI()
         }
     },
 )
-async def read_item(item_id: str, img: Optional[bool] = None):
+async def read_item(item_id: str, img: Union[bool, None] = None):
     if img:
         return FileResponse("image.png", media_type="image/png")
     else:

docs_src/additional_responses/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.responses import FileResponse
@@ -25,7 +25,7 @@ app = FastAPI()
     response_model=Item,
     responses={**responses, 200: {"content": {"image/png": {}}}},
 )
-async def read_item(item_id: str, img: Optional[bool] = None):
+async def read_item(item_id: str, img: Union[bool, None] = None):
     if img:
         return FileResponse("image.png", media_type="image/png")
     else:

docs_src/background_tasks/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import BackgroundTasks, Depends, FastAPI
 
@@ -10,7 +10,7 @@ def write_log(message: str):
         log.write(message)
 
 
-def get_query(background_tasks: BackgroundTasks, q: Optional[str] = None):
+def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
     if q:
         message = f"found query: {q}\n"
         background_tasks.add_task(write_log, message)

docs_src/body/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -6,9 +6,9 @@ from pydantic import BaseModel
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()

docs_src/body/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -6,9 +6,9 @@ from pydantic import BaseModel
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()

docs_src/body/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -6,9 +6,9 @@ from pydantic import BaseModel
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()

docs_src/body/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -6,16 +6,16 @@ from pydantic import BaseModel
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()
 
 
 @app.put("/items/{item_id}")
-async def create_item(item_id: int, item: Item, q: Optional[str] = None):
+async def create_item(item_id: int, item: Item, q: Union[str, None] = None):
     result = {"item_id": item_id, **item.dict()}
     if q:
         result.update({"q": q})

docs_src/body_multiple_params/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,14 +8,14 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 class User(BaseModel):
     username: str
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: list = []
 
 

docs_src/body_nested_models/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: List[str] = []
 
 

docs_src/body_nested_models/tutorial002_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: list[str] = []
 
 

docs_src/body_nested_models/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/body_nested_models/tutorial003_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/body_nested_models/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
-    image: Optional[Image] = None
+    image: Union[Image, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial004_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
-    image: Optional[Image] = None
+    image: Union[Image, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial005.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
-    image: Optional[Image] = None
+    image: Union[Image, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial005_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
-    image: Optional[Image] = None
+    image: Union[Image, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial006.py

@@ -1,4 +1,4 @@
-from typing import List, Optional, Set
+from typing import List, Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
-    images: Optional[List[Image]] = None
+    images: Union[List[Image], None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial006_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,11 +13,11 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
-    images: Optional[list[Image]] = None
+    images: Union[list[Image], None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/body_nested_models/tutorial007.py

@@ -1,4 +1,4 @@
-from typing import List, Optional, Set
+from typing import List, Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,16 +13,16 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
-    images: Optional[List[Image]] = None
+    images: Union[List[Image], None] = None
 
 
 class Offer(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     items: List[Item]
 

docs_src/body_nested_models/tutorial007_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -13,16 +13,16 @@ class Image(BaseModel):
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
-    images: Optional[list[Image]] = None
+    images: Union[list[Image], None] = None
 
 
 class Offer(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     items: list[Item]
 

docs_src/body_updates/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: Optional[str] = None
-    description: Optional[str] = None
-    price: Optional[float] = None
+    name: Union[str, None] = None
+    description: Union[str, None] = None
+    price: Union[float, None] = None
     tax: float = 10.5
     tags: List[str] = []
 

docs_src/body_updates/tutorial001_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: Optional[str] = None
-    description: Optional[str] = None
-    price: Optional[float] = None
+    name: Union[str, None] = None
+    description: Union[str, None] = None
+    price: Union[float, None] = None
     tax: float = 10.5
     tags: list[str] = []
 

docs_src/body_updates/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: Optional[str] = None
-    description: Optional[str] = None
-    price: Optional[float] = None
+    name: Union[str, None] = None
+    description: Union[str, None] = None
+    price: Union[float, None] = None
     tax: float = 10.5
     tags: List[str] = []
 

docs_src/body_updates/tutorial002_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -8,9 +8,9 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    name: Optional[str] = None
-    description: Optional[str] = None
-    price: Optional[float] = None
+    name: Union[str, None] = None
+    description: Union[str, None] = None
+    price: Union[float, None] = None
     tax: float = 10.5
     tags: list[str] = []
 

docs_src/dataclasses/tutorial001.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -8,8 +8,8 @@ from fastapi import FastAPI
 class Item:
     name: str
     price: float
-    description: Optional[str] = None
-    tax: Optional[float] = None
+    description: Union[str, None] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()

docs_src/dataclasses/tutorial002.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass, field
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 
@@ -9,8 +9,8 @@ class Item:
     name: str
     price: float
     tags: List[str] = field(default_factory=list)
-    description: Optional[str] = None
-    tax: Optional[float] = None
+    description: Union[str, None] = None
+    tax: Union[float, None] = None
 
 
 app = FastAPI()

docs_src/dataclasses/tutorial003.py

@@ -1,5 +1,5 @@
 from dataclasses import field  # (1)
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from pydantic.dataclasses import dataclass  # (2)
@@ -8,7 +8,7 @@ from pydantic.dataclasses import dataclass  # (2)
 @dataclass
 class Item:
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 @dataclass

docs_src/dependencies/tutorial001.py

@@ -1,11 +1,13 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 
 app = FastAPI()
 
 
-async def common_parameters(q: Optional[str] = None, skip: int = 0, limit: int = 100):
+async def common_parameters(
+    q: Union[str, None] = None, skip: int = 0, limit: int = 100
+):
     return {"q": q, "skip": skip, "limit": limit}
 
 

docs_src/dependencies/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 
@@ -9,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit

docs_src/dependencies/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 
@@ -9,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit

docs_src/dependencies/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 
@@ -9,7 +9,7 @@ fake_items_db = [{"item_name": "Foo"}, {"item_name": "Bar"}, {"item_name": "Baz"
 
 
 class CommonQueryParams:
-    def __init__(self, q: Optional[str] = None, skip: int = 0, limit: int = 100):
+    def __init__(self, q: Union[str, None] = None, skip: int = 0, limit: int = 100):
         self.q = q
         self.skip = skip
         self.limit = limit

docs_src/dependencies/tutorial005.py

@@ -1,16 +1,17 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Cookie, Depends, FastAPI
 
 app = FastAPI()
 
 
-def query_extractor(q: Optional[str] = None):
+def query_extractor(q: Union[str, None] = None):
     return q
 
 
 def query_or_cookie_extractor(
-    q: str = Depends(query_extractor), last_query: Optional[str] = Cookie(default=None)
+    q: str = Depends(query_extractor),
+    last_query: Union[str, None] = Cookie(default=None),
 ):
     if not q:
         return last_query

docs_src/dependency_testing/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 from fastapi.testclient import TestClient
@@ -6,7 +6,9 @@ from fastapi.testclient import TestClient
 app = FastAPI()
 
 
-async def common_parameters(q: Optional[str] = None, skip: int = 0, limit: int = 100):
+async def common_parameters(
+    q: Union[str, None] = None, skip: int = 0, limit: int = 100
+):
     return {"q": q, "skip": skip, "limit": limit}
 
 
@@ -23,7 +25,7 @@ async def read_users(commons: dict = Depends(common_parameters)):
 client = TestClient(app)
 
 
-async def override_dependency(q: Optional[str] = None):
+async def override_dependency(q: Union[str, None] = None):
     return {"q": q, "skip": 5, "limit": 10}
 
 

docs_src/encoder/tutorial001.py

@@ -1,5 +1,5 @@
 from datetime import datetime
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -11,7 +11,7 @@ fake_db = {}
 class Item(BaseModel):
     title: str
     timestamp: datetime
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 app = FastAPI()

docs_src/extra_data_types/tutorial001.py

@@ -1,5 +1,5 @@
 from datetime import datetime, time, timedelta
-from typing import Optional
+from typing import Union
 from uuid import UUID
 
 from fastapi import Body, FastAPI
@@ -10,10 +10,10 @@ app = FastAPI()
 @app.put("/items/{item_id}")
 async def read_items(
     item_id: UUID,
-    start_datetime: Optional[datetime] = Body(default=None),
-    end_datetime: Optional[datetime] = Body(default=None),
-    repeat_at: Optional[time] = Body(default=None),
-    process_after: Optional[timedelta] = Body(default=None),
+    start_datetime: Union[datetime, None] = Body(default=None),
+    end_datetime: Union[datetime, None] = Body(default=None),
+    repeat_at: Union[time, None] = Body(default=None),
+    process_after: Union[timedelta, None] = Body(default=None),
 ):
     start_process = start_datetime + process_after
     duration = end_datetime - start_process

docs_src/extra_models/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
@@ -10,20 +10,20 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 class UserOut(BaseModel):
     username: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 class UserInDB(BaseModel):
     username: str
     hashed_password: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 def fake_password_hasher(raw_password: str):

docs_src/extra_models/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
@@ -9,7 +9,7 @@ app = FastAPI()
 class UserBase(BaseModel):
     username: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 class UserIn(UserBase):

docs_src/header_params/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI, Header
 
@@ -6,5 +6,5 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(user_agent: Optional[str] = Header(default=None)):
+async def read_items(user_agent: Union[str, None] = Header(default=None)):
     return {"User-Agent": user_agent}

docs_src/header_params/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI, Header
 
@@ -7,6 +7,6 @@ app = FastAPI()
 
 @app.get("/items/")
 async def read_items(
-    strange_header: Optional[str] = Header(default=None, convert_underscores=False)
+    strange_header: Union[str, None] = Header(default=None, convert_underscores=False)
 ):
     return {"strange_header": strange_header}

docs_src/header_params/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI, Header
 
@@ -6,5 +6,5 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(x_token: Optional[List[str]] = Header(default=None)):
+async def read_items(x_token: Union[List[str], None] = Header(default=None)):
     return {"X-Token values": x_token}

docs_src/header_params/tutorial003_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI, Header
 
@@ -6,5 +6,5 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(x_token: Optional[list[str]] = Header(default=None)):
+async def read_items(x_token: Union[list[str], None] = Header(default=None)):
     return {"X-Token values": x_token}

docs_src/nosql_databases/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from couchbase import LOCKMODE_WAIT
 from couchbase.bucket import Bucket
@@ -23,9 +23,9 @@ def get_bucket():
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 class UserInDB(User):

docs_src/openapi_callbacks/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import APIRouter, FastAPI
 from pydantic import BaseModel, HttpUrl
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Invoice(BaseModel):
     id: str
-    title: Optional[str] = None
+    title: Union[str, None] = None
     customer: str
     total: float
 
@@ -33,7 +33,7 @@ def invoice_notification(body: InvoiceEvent):
 
 
 @app.post("/invoices/", callbacks=invoices_callback_router.routes)
-def create_invoice(invoice: Invoice, callback_url: Optional[HttpUrl] = None):
+def create_invoice(invoice: Invoice, callback_url: Union[HttpUrl, None] = None):
     """
     Create an invoice.
 

docs_src/path_operation_advanced_configuration/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI, status
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial001_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI, status
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial002_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial003_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial004_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial005.py

@@ -1,4 +1,4 @@
-from typing import Optional, Set
+from typing import Set, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: Set[str] = set()
 
 

docs_src/path_operation_configuration/tutorial005_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: set[str] = set()
 
 

docs_src/python_types/tutorial009c.py

@@ -0,0 +1,5 @@
+from typing import Optional
+
+
+def say_hi(name: Optional[str]):
+    print(f"Hey {name}!")

docs_src/python_types/tutorial009c_py310.py

@@ -0,0 +1,2 @@
+def say_hi(name: str | None):
+    print(f"Hey {name}!")

docs_src/python_types/tutorial011.py

@@ -1,5 +1,5 @@
 from datetime import datetime
-from typing import List, Optional
+from typing import List, Union
 
 from pydantic import BaseModel
 
@@ -7,7 +7,7 @@ from pydantic import BaseModel
 class User(BaseModel):
     id: int
     name = "John Doe"
-    signup_ts: Optional[datetime] = None
+    signup_ts: Union[datetime, None] = None
     friends: List[int] = []
 
 

docs_src/python_types/tutorial011_py39.py

@@ -1,5 +1,5 @@
 from datetime import datetime
-from typing import Optional
+from typing import Union
 
 from pydantic import BaseModel
 
@@ -7,7 +7,7 @@ from pydantic import BaseModel
 class User(BaseModel):
     id: int
     name = "John Doe"
-    signup_ts: Optional[datetime] = None
+    signup_ts: Union[datetime, None] = None
     friends: list[int] = []
 
 

docs_src/python_types/tutorial012.py

@@ -0,0 +1,8 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class User(BaseModel):
+    name: str
+    age: Optional[int]

docs_src/query_params/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -6,7 +6,7 @@ app = FastAPI()
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: str, q: Optional[str] = None):
+async def read_item(item_id: str, q: Union[str, None] = None):
     if q:
         return {"item_id": item_id, "q": q}
     return {"item_id": item_id}

docs_src/query_params/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -6,7 +6,7 @@ app = FastAPI()
 
 
 @app.get("/items/{item_id}")
-async def read_item(item_id: str, q: Optional[str] = None, short: bool = False):
+async def read_item(item_id: str, q: Union[str, None] = None, short: bool = False):
     item = {"item_id": item_id}
     if q:
         item.update({"q": q})

docs_src/query_params/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -7,7 +7,7 @@ app = FastAPI()
 
 @app.get("/users/{user_id}/items/{item_id}")
 async def read_user_item(
-    user_id: int, item_id: str, q: Optional[str] = None, short: bool = False
+    user_id: int, item_id: str, q: Union[str, None] = None, short: bool = False
 ):
     item = {"item_id": item_id, "owner_id": user_id}
     if q:

docs_src/query_params/tutorial006.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -7,7 +7,7 @@ app = FastAPI()
 
 @app.get("/items/{item_id}")
 async def read_user_item(
-    item_id: str, needy: str, skip: int = 0, limit: Optional[int] = None
+    item_id: str, needy: str, skip: int = 0, limit: Union[int, None] = None
 ):
     item = {"item_id": item_id, "needy": needy, "skip": skip, "limit": limit}
     return item

docs_src/query_params_str_validations/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 
@@ -6,7 +6,7 @@ app = FastAPI()
 
 
 @app.get("/items/")
-async def read_items(q: Optional[str] = None):
+async def read_items(q: Union[str, None] = None):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})

docs_src/request_files/tutorial001_02.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI, File, UploadFile
 
@@ -6,7 +6,7 @@ app = FastAPI()
 
 
 @app.post("/files/")
-async def create_file(file: Optional[bytes] = File(default=None)):
+async def create_file(file: Union[bytes, None] = File(default=None)):
     if not file:
         return {"message": "No file sent"}
     else:
@@ -14,7 +14,7 @@ async def create_file(file: Optional[bytes] = File(default=None)):
 
 
 @app.post("/uploadfile/")
-async def create_upload_file(file: Optional[UploadFile] = None):
+async def create_upload_file(file: Union[UploadFile, None] = None):
     if not file:
         return {"message": "No upload file sent"}
     else:

docs_src/response_directly/tutorial001.py

@@ -1,5 +1,5 @@
 from datetime import datetime
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from fastapi.encoders import jsonable_encoder
@@ -10,7 +10,7 @@ from pydantic import BaseModel
 class Item(BaseModel):
     title: str
     timestamp: datetime
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 app = FastAPI()

docs_src/response_model/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: List[str] = []
 
 

docs_src/response_model/tutorial001_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
     tags: list[str] = []
 
 

docs_src/response_model/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
@@ -10,7 +10,7 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 # Don't do this in production!

docs_src/response_model/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, EmailStr
@@ -10,13 +10,13 @@ class UserIn(BaseModel):
     username: str
     password: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 class UserOut(BaseModel):
     username: str
     email: EmailStr
-    full_name: Optional[str] = None
+    full_name: Union[str, None] = None
 
 
 @app.post("/user/", response_model=UserOut)

docs_src/response_model/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     tax: float = 10.5
     tags: List[str] = []

docs_src/response_model/tutorial004_py39.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     tax: float = 10.5
     tags: list[str] = []

docs_src/response_model/tutorial005.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     tax: float = 10.5
 

docs_src/response_model/tutorial006.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
     tax: float = 10.5
 

docs_src/schema_extra_example/tutorial001.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
     class Config:
         schema_extra = {

docs_src/schema_extra_example/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import FastAPI
 from pydantic import BaseModel, Field
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str = Field(example="Foo")
-    description: Optional[str] = Field(default=None, example="A very nice Item")
+    description: Union[str, None] = Field(default=None, example="A very nice Item")
     price: float = Field(example=35.4)
-    tax: Optional[float] = Field(default=None, example=3.2)
+    tax: Union[float, None] = Field(default=None, example=3.2)
 
 
 @app.put("/items/{item_id}")

docs_src/schema_extra_example/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/schema_extra_example/tutorial004.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Body, FastAPI
 from pydantic import BaseModel
@@ -8,9 +8,9 @@ app = FastAPI()
 
 class Item(BaseModel):
     name: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
     price: float
-    tax: Optional[float] = None
+    tax: Union[float, None] = None
 
 
 @app.put("/items/{item_id}")

docs_src/security/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI
 from fastapi.security import OAuth2PasswordBearer
@@ -11,9 +11,9 @@ oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 def fake_decode_token(token):

docs_src/security/tutorial003.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI, HTTPException, status
 from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
@@ -33,9 +33,9 @@ oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 class UserInDB(User):

docs_src/security/tutorial004.py

@@ -1,5 +1,5 @@
 from datetime import datetime, timedelta
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI, HTTPException, status
 from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
@@ -31,14 +31,14 @@ class Token(BaseModel):
 
 
 class TokenData(BaseModel):
-    username: Optional[str] = None
+    username: Union[str, None] = None
 
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 class UserInDB(User):
@@ -75,7 +75,7 @@ def authenticate_user(fake_db, username: str, password: str):
     return user
 
 
-def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
+def create_access_token(data: dict, expires_delta: Union[timedelta, None] = None):
     to_encode = data.copy()
     if expires_delta:
         expire = datetime.utcnow() + expires_delta

docs_src/security/tutorial005.py

@@ -1,5 +1,5 @@
 from datetime import datetime, timedelta
-from typing import List, Optional
+from typing import List, Union
 
 from fastapi import Depends, FastAPI, HTTPException, Security, status
 from fastapi.security import (
@@ -42,15 +42,15 @@ class Token(BaseModel):
 
 
 class TokenData(BaseModel):
-    username: Optional[str] = None
+    username: Union[str, None] = None
     scopes: List[str] = []
 
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 class UserInDB(User):
@@ -90,7 +90,7 @@ def authenticate_user(fake_db, username: str, password: str):
     return user
 
 
-def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
+def create_access_token(data: dict, expires_delta: Union[timedelta, None] = None):
     to_encode = data.copy()
     if expires_delta:
         expire = datetime.utcnow() + expires_delta

docs_src/security/tutorial005_py39.py

@@ -1,5 +1,5 @@
 from datetime import datetime, timedelta
-from typing import Optional
+from typing import Union
 
 from fastapi import Depends, FastAPI, HTTPException, Security, status
 from fastapi.security import (
@@ -42,15 +42,15 @@ class Token(BaseModel):
 
 
 class TokenData(BaseModel):
-    username: Optional[str] = None
+    username: Union[str, None] = None
     scopes: list[str] = []
 
 
 class User(BaseModel):
     username: str
-    email: Optional[str] = None
-    full_name: Optional[str] = None
-    disabled: Optional[bool] = None
+    email: Union[str, None] = None
+    full_name: Union[str, None] = None
+    disabled: Union[bool, None] = None
 
 
 class UserInDB(User):
@@ -90,7 +90,7 @@ def authenticate_user(fake_db, username: str, password: str):
     return user
 
 
-def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
+def create_access_token(data: dict, expires_delta: Union[timedelta, None] = None):
     to_encode = data.copy()
     if expires_delta:
         expire = datetime.utcnow() + expires_delta

docs_src/sql_databases/sql_app/schemas.py

@@ -1,11 +1,11 @@
-from typing import List, Optional
+from typing import List, Union
 
 from pydantic import BaseModel
 
 
 class ItemBase(BaseModel):
     title: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 class ItemCreate(ItemBase):

docs_src/sql_databases/sql_app_py39/schemas.py

@@ -1,11 +1,11 @@
-from typing import Optional
+from typing import Union
 
 from pydantic import BaseModel
 
 
 class ItemBase(BaseModel):
     title: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 class ItemCreate(ItemBase):

docs_src/sql_databases_peewee/sql_app/schemas.py

@@ -1,4 +1,4 @@
-from typing import Any, List, Optional
+from typing import Any, List, Union
 
 import peewee
 from pydantic import BaseModel
@@ -15,7 +15,7 @@ class PeeweeGetterDict(GetterDict):
 
 class ItemBase(BaseModel):
     title: str
-    description: Optional[str] = None
+    description: Union[str, None] = None
 
 
 class ItemCreate(ItemBase):

docs_src/websockets/tutorial002.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Union
 
 from fastapi import Cookie, Depends, FastAPI, Query, WebSocket, status
 from fastapi.responses import HTMLResponse
@@ -57,8 +57,8 @@ async def get():
 
 async def get_cookie_or_token(
     websocket: WebSocket,
-    session: Optional[str] = Cookie(default=None),
-    token: Optional[str] = Query(default=None),
+    session: Union[str, None] = Cookie(default=None),
+    token: Union[str, None] = Query(default=None),
 ):
     if session is None and token is None:
         await websocket.close(code=status.WS_1008_POLICY_VIOLATION)
@@ -69,7 +69,7 @@ async def get_cookie_or_token(
 async def websocket_endpoint(
     websocket: WebSocket,
     item_id: str,
-    q: Optional[int] = None,
+    q: Union[int, None] = None,
     cookie_or_token: str = Depends(get_cookie_or_token),
 ):
     await websocket.accept()