此处，`shutdown` 事件处理器函数在 `log.txt` 中写入一行文本 `Application shutdown`。

/// info | 说明

`open()` 函数中，`mode="a"` 指的是**追加**。因此这行文本会添加在文件已有内容之后，不会覆盖之前的内容。

///

/// tip | 提示

注意，本例使用 Python `open()` 标准函数与文件交互。

这个函数执行 I/O（输入/输出）操作，需要等待内容写进磁盘。

但 `open()` 函数不支持使用 `async` 与 `await`。

因此，声明事件处理函数要使用 `def`，不能使用 `asnyc def`。

///

### `startup` 和 `shutdown` 一起使用

    private static final int STRUCTURE_SIZE = 16;

    private byte[] fileId; // 16-byte file ID from previous open

    /**
     * Create a new durable handle reconnect context
     * @param fileId the 16-byte file ID from the previous open
     */
    public DurableHandleReconnect(byte[] fileId) {
        if (fileId.length != 16) {

    with path.open("rb") as file:
        response = client.post("/files/", files={"file": file})
    assert response.status_code == 200, response.text
    assert response.json() == {"file_size": 14}


def test_post_upload_file(tmp_path: Path, client: TestClient):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

    with path.open("rb") as file:

)

func TestNewPReader(t *testing.T) {
	files, err := os.ReadDir("testdata")
	if err != nil {
		t.Fatal(err)
	}
	for _, file := range files {
		t.Run(file.Name(), func(t *testing.T) {
			f, err := os.Open(filepath.Join("testdata", file.Name()))
			if err != nil {
				t.Fatal(err)
			}
			r := NewPReader(f, &ReaderArgs{})
			var record sql.Record
			for {
				record, err = r.Read(record)
				if err != nil {

)

func TestNewReader(t *testing.T) {
	files, err := os.ReadDir("testdata")
	if err != nil {
		t.Fatal(err)
	}
	for _, file := range files {
		t.Run(file.Name(), func(t *testing.T) {
			f, err := os.Open(filepath.Join("testdata", file.Name()))
			if err != nil {
				t.Fatal(err)
			}
			r := NewReader(f, &ReaderArgs{})
			var record sql.Record
			for {
				record, err = r.Read(record)
				if err != nil {

	fmt.Fprintf(w, "\tfunction name\n")
	fmt.Fprintf(w, "\tfile:line\n")
}

func usage() {
	printUsage(os.Stderr)
	os.Exit(2)
}

func main() {
	log.SetFlags(0)
	log.SetPrefix("addr2line: ")
	counter.Open()

	// pprof expects this behavior when checking for addr2line
	if len(os.Args) > 1 && os.Args[1] == "--help" {
		printUsage(os.Stdout)
		os.Exit(0)
	}

	flag.Usage = usage
	flag.Parse()

)

// AppendFile - appends the file "src" to the file "dst"
func AppendFile(dst string, src string, osync bool) error {
	appendFile, err := lock.Open(dst, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0o666)
	if err != nil {
		return err
	}
	defer appendFile.Close()

	srcFile, err := lock.Open(src, os.O_RDONLY, 0o666)
	if err != nil {
		return err
	}
	defer srcFile.Close()
	_, err = io.Copy(appendFile, srcFile)
	return err

	untranslatedErr := errors.New("some random error")
	db, _ := gorm.Open(tests.DummyDialector{TranslatedErr: translatedErr})

	err := db.AddError(untranslatedErr)
	if !errors.Is(err, untranslatedErr) {
		t.Fatalf("expected err: %v got err: %v", untranslatedErr, err)
	}

	// it should translate error when the TranslateError flag is true
	db, _ = gorm.Open(tests.DummyDialector{TranslatedErr: translatedErr}, &gorm.Config{TranslateError: true})

{* ../../docs_src/events/tutorial003_py39.py hl[1,13] *}

Un **context manager** en Python es algo que puedes usar en un statement `with`, por ejemplo, `open()` puede ser usado como un context manager:

```Python
with open("file.txt") as file:
    file.read()
```

En versiones recientes de Python, también hay un **async context manager**. Lo usarías con `async with`:

```Python

 *
 * This test includes tests from [Guava's](https://code.google.com/p/guava-libraries/)
 * MediaTypeTest.
 */
open class MediaTypeTest {
  open fun MediaType.charsetName(): String? = parameter("charset")?.uppercase()

  protected open fun parse(string: String): MediaType = string.toMediaTypeOrNull()!!

  protected open fun assertInvalid(
    string: String,
    exceptionMessage: String?,
  ) {