0 1px 0 #fff;\n  opacity: .5;\n}\n\n.close:hover {\n  color: #000;\n  text-decoration: none;\n}\n\n.close:not(:disabled):not(.disabled):hover, .close:not(:disabled):not(.disabled):focus {\n  opacity: .75;\n}\n\nbutton.close {\n  padding: 0;\n  background-color: transparent;\n  border: 0;\n  -webkit-appearance: none;\n  -moz-appearance: none;\n  appearance: none;\n}\n\na.close.disabled {\n  pointer-events: none;\n}\n\n.toast {\n  max-width: 350px;\n  overflow: hidden;\n  font-size: 0.875rem;\n  background-color:...

    # o procedureSynonymHandlingType: (NotRequired - Default NONE)
    #  You can specify the handling type of procedure synonym.
    #   NONE - No handling. (default)
    #   INCLUDE - It includes procedure synonyms.
    #   SWITCH - It switches all normal procedures to procedure synonyms.
    #
    #; procedureSynonymHandlingType = NONE
    # - - - - - - - - - -/

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="9  11-12"
{!> ../../docs_src/response_model/tutorial004_py310.py!}
```

////

* `description: Union[str, None] = None` (⚖️ `str | None = None` 🐍 3️⃣.1️⃣0️⃣) ✔️ 🔢 `None`.
* `tax: float = 10.5` ✔️ 🔢 `10.5`.
* `tags: List[str] = []` 🔢 🛁 📇: `[]`.

✋️ 👆 💪 💚 🚫 👫 ⚪️➡️ 🏁 🚥 👫 🚫 🤙 🏪.

    response = client.get("/users/")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "message": "Hello Users!",
        "params": {"q": None, "skip": 5, "limit": 10},
    }


@needs_py310
def test_override_in_users_with_q():
    from docs_src.dependency_testing.tutorial001_py310 import client

    response = client.get("/users/?q=foo")

    rules:
      - apiGroups:
          - ""
        apiVersions:
          - v1
        operations:
          - CREATE
        resources:
          - pods
        scope: '*'
    sideEffects: None
    timeoutSeconds: 10
  - admissionReviewVersions:
      - v1beta1
      - v1
    clientConfig:
      service:
        name: istiod-1-16
        namespace: istio-system
        path: /inject

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

Tin tốt là, khi bạn sử dụng Python 3.10, bạn sẽ không phải lo lắng về điều đó, bạn sẽ có thể sử dụng `|` để định nghĩa hợp của các kiểu dữ liệu một cách đơn giản:

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009c_py310.py!}
```

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

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////

//// tab | Python 3.8+

```Python hl_lines="11  13-14"
{!> ../../docs_src/response_model/tutorial004.py!}
```

////

* `description: Union[str, None] = None` (oder `str | None = None` in Python 3.10) hat einen Defaultwert `None`.
* `tax: float = 10.5` hat einen Defaultwert `10.5`.
* `tags: List[str] = []` hat eine leere Liste als Defaultwert: `[]`.