```Python hl_lines="2  7-10 23-25"
from fastapi import FastAPI
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):

                "count": count,
                "avatarUrl": author.avatarUrl,
                "url": author.url,
            }
    return users


def update_content(*, content_path: Path, new_content: Any) -> bool:
    old_content = content_path.read_text(encoding="utf-8")

    new_content = yaml.dump(new_content, sort_keys=False, width=200, allow_unicode=True)
    if old_content == new_content:

	// Create new HTTP listener.
	var listener *httpListener
	listener, listenErrs := newHTTPListener(
		listenCtx,
		srv.Addrs,
		srv.TCPOptions,
	)

	var interfaceFound bool
	for i := range listenErrs {
		if listenErrs[i] != nil {
			listenErrCallback(srv.Addrs[i], listenErrs[i])
		} else {
			interfaceFound = true
		}
	}
	if !interfaceFound {

//
//	e.g. Send the log to a http server
type Target interface {
	String() string
	Endpoint() string
	Stats() types.TargetStats
	Init(ctx context.Context) error
	IsOnline(ctx context.Context) bool
	Cancel()
	Send(ctx context.Context, entry any) error
	Type() types.TargetType
}

type targetsList struct {
	list []Target
	mu   sync.RWMutex
}

func newTargetsList() *targetsList {

  virtual absl::Status SetAttrInt(const char* attr_name, int64_t value) = 0;
  virtual absl::Status SetAttrFloat(const char* attr_name, float value) = 0;
  virtual absl::Status SetAttrBool(const char* attr_name, bool value) = 0;
  virtual absl::Status SetAttrType(const char* attr_name, DataType value) = 0;
  virtual absl::Status SetAttrShape(const char* attr_name, const int64_t* dims,
                                    const int num_dims) = 0;

# Python 型別入門 { #python-types-intro }

Python 支援可選用的「型別提示」（也稱為「型別註記」）。

這些「型別提示」或註記是一種特殊語法，用來宣告變數的<dfn title="例如：str、int、float、bool">型別</dfn>。

為你的變數宣告型別後，編輯器與工具就能提供更好的支援。

這裡只是關於 Python 型別提示的快速教學／複習。它只涵蓋使用在 **FastAPI** 時所需的最低限度...其實非常少。

**FastAPI** 完全是以這些型別提示為基礎，並因此帶來許多優勢與好處。

但就算你從不使用 **FastAPI**，學一點型別提示也會有幫助。

/// note | 注意

如果你是 Python 專家，而且已經完全了解型別提示，可以直接跳到下一章。

///

## 動機 { #motivation }

先從一個簡單的例子開始：

	var (
		counter int
		mv      *MetaValue
		body    = `{ "bio": "bada bing bada boom", "id": 1, "name": "Charles" }
{ "bio": "bada bing bada boom", "id": 2, "name": "Charles" }
{ "bio": "bada bing bada boom", "id": 3, "name": "Charles" }
{ "bio": "bada bing bada boom", "id": 4, "name": "Charles" }
{ "bio": "bada bing bada boom", "id": 5, "name": "Charles" }
`
	)

	decoder := NewDecoder(mkReader(body), 0)

	ReqParams    map[string]string
	RespElements map[string]string
	Host         string
	UserAgent    string
}

// ToEvent - converts to notification event.
func (args eventArgs) ToEvent(escape bool) event.Event {
	eventTime := UTCNow()
	uniqueID := fmt.Sprintf("%X", eventTime.UnixNano())
	if !args.Object.ModTime.IsZero() {
		uniqueID = fmt.Sprintf("%X", args.Object.ModTime.UnixNano())
	}

	// Prints documentation message.
	printObjectAPIMsg()
	if globalIsDistErasure {
		logger.Startup(color.Bold(banner))
	}
}

// Returns true if input is IPv6
func isIPv6(host string) bool {
	h, _, err := net.SplitHostPort(host)
	if err != nil {
		h = host
	}
	ip := net.ParseIP(h)
	return ip.To16() != nil && ip.To4() == nil
}

// strip api endpoints list with standard ports such as

// Case 4: bytes=-30 (suffix length specification) -> RangeSpec{true, -30, -1}
type HTTPRangeSpec struct {
	// Does the range spec refer to a suffix of the object?
	IsSuffixLength bool

	// Start and end offset specified in range spec
	Start, End int64
}

// GetLength - get length of range
func (h *HTTPRangeSpec) GetLength(resourceSize int64) (rangeLength int64, err error) {
	switch {