def write_action_env_to_bazelrc(var_name, var):
  write_to_bazelrc('build --action_env {}="{}"'.format(var_name, str(var)))


def write_repo_env_to_bazelrc(config_name, var_name, var):
  write_to_bazelrc(
      'build:{} --repo_env {}="{}"'.format(config_name, var_name, str(var))
  )


def run_shell(cmd, allow_non_zero=False, stderr=None):
  if stderr is None:
    stderr = sys.stdout

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool | None = None


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


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


@app.put("/items/{item_id}")

You can use the `jsonable_encoder` to convert the input data to data that can be stored as JSON (e.g. with a NoSQL database). For example, converting `datetime` to `str`.

{* ../../docs_src/body_updates/tutorial001_py310.py hl[28:33] *}

`PUT` is used to receive data that should replace the existing data.

### Warning about replacing { #warning-about-replacing }

app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl="/token",
    description="OAuth2PasswordBearer security scheme",
    auto_error=False,
)


@app.get("/items/")
async def read_items(token: str | None = Security(oauth2_scheme)):
    if token is None:
        return {"msg": "Create an account first"}
    return {"token": token}


client = TestClient(app)


def test_no_token():

        openapi_url=app.openapi_url,
        title=app.title + " - ReDoc",
        redoc_js_url="/static/redoc.standalone.js",
    )


@app.get("/users/{username}")
async def read_user(username: str):

        circuitBreaker.call(() -> "success");

        SimpleCircuitBreaker.Statistics stats = circuitBreaker.getStatistics();
        String str = stats.toString();

        assertNotNull(str);
        assertTrue(str.contains("test"));
        assertTrue(str.contains("CLOSED"));
        assertTrue(str.contains("100.00%"));
    }

    @Test
    @DisplayName("Test mixed success and failure pattern")

Your response model could have default values, like:

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (or `str | None = None` in Python 3.10) has a default of `None`.
* `tax: float = 10.5` has a default of `10.5`.
* `tags: List[str] = []` has a default of an empty list: `[]`.

but you might want to omit them from the result if they were not actually stored.

`@lru_cache` 會修改它所裝飾的函式，使其回傳第一次回傳的相同值，而不是每次都重新計算、執行函式碼。

因此，被裝飾的函式對於每組參數組合只會執行一次。之後，凡是以完全相同參數組合呼叫時，都會重複使用先前對應的回傳值。

例如，如果你有一個函式：

```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

你的程式可能會這樣執行：

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()

路徑參數一定是必填，因為它必須是路徑的一部分。即使你將其宣告為 `None` 或設定預設值，也不會有任何影響，它仍然是必填。

///

## 依需求調整參數順序 { #order-the-parameters-as-you-need }

/// tip

如果你使用 `Annotated`，這點大概沒那麼重要或必要。

///

假設你想把查詢參數 `q` 宣告為必要的 `str`。

而你不需要為該參數宣告其他內容，所以其實不需要用 `Query`。

但你仍需要為路徑參數 `item_id` 使用 `Path`，而且基於某些理由你不想用 `Annotated`。

如果你把有「預設值」的參數放在沒有「預設值」的參數之前，Python 會抱怨。

但你可以調整它們的順序，先放沒有預設值（查詢參數 `q`）的參數。

/// tip

This is probably not as important or necessary if you use `Annotated`.

///

Let's say that you want to declare the query parameter `q` as a required `str`.

And you don't need to declare anything else for that parameter, so you don't really need to use `Query`.

But you still need to use `Path` for the `item_id` path parameter. And you don't want to use `Annotated` for some reason.