String checksumFileExtension,
            Wagon wagon)
            throws ResourceDoesNotExistException, TransferFailedException, AuthorizationException {
        try {
            // grab it first, because it's about to change...
            String actualChecksum = checksumObserver.getActualChecksum();

            File tempChecksumFile = new File(tempDestination + checksumFileExtension + ".tmp");

# Những bước đầu tiên

Tệp tin FastAPI đơn giản nhất có thể trông như này:

{* ../../docs_src/first_steps/tutorial001.py *}

Sao chép sang một tệp tin `main.py`.

Chạy live server:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]

"cos", "cun", "cuns", "cunha", "cunhas", "da", "dalgunha", "dalgunhas", "dalgún", "dalgúns", "das", "de", "del", "dela", "delas", "deles", "desde", "deste", "do", "dos", "dun", "duns", "dunha", "dunhas", "e", "el", "ela", "elas", "eles", "en", "era", "eran", "esa", "esas", "ese", "eses", "esta", "estar", "estaba", "está", "están", "este", "estes", "estiven", "estou", "eu", "é", "facer", "foi", "foron", "fun", "había", "hai", "iso", "isto", "la", "las", "lle", "lles", "lo", "los", "mais", "me", "meu",...

"cos", "cun", "cuns", "cunha", "cunhas", "da", "dalgunha", "dalgunhas", "dalgún", "dalgúns", "das", "de", "del", "dela", "delas", "deles", "desde", "deste", "do", "dos", "dun", "duns", "dunha", "dunhas", "e", "el", "ela", "elas", "eles", "en", "era", "eran", "esa", "esas", "ese", "eses", "esta", "estar", "estaba", "está", "están", "este", "estes", "estiven", "estou", "eu", "é", "facer", "foi", "foron", "fun", "había", "hai", "iso", "isto", "la", "las", "lle", "lles", "lo", "los", "mais", "me", "meu",...

pkg image, method (*Alpha) AlphaAt(int, int) color.Alpha
pkg image, method (*Alpha16) Alpha16At(int, int) color.Alpha16
pkg image, method (*Gray) GrayAt(int, int) color.Gray
pkg image, method (*Gray16) Gray16At(int, int) color.Gray16
pkg image, method (*NRGBA) NRGBAAt(int, int) color.NRGBA
pkg image, method (*NRGBA64) NRGBA64At(int, int) color.NRGBA64

          if (protocolNegotiationEnabled) {
            Platform.get().configureTlsExtensions(sslSocket, null, protocols)
          }

          sslSocket.startHandshake()

          // Wait until after handshake to grab the buffered socket
          socket = MockWebServerSocket(sslSocket)

          if (protocolNegotiationEnabled) {
            val protocolString = Platform.get().getSelectedProtocol(sslSocket)
            protocol =

    while (taskFaker.isIdle()) {
      set("a", "a", "a")
      set("b", "b", "b")
    }
    val commitEditor = cache.edit("c")!!
    val abortEditor = cache.edit("d")!!
    cache.edit("e") // Grab an editor, but don't do anything with it.

    // Cause the rebuild action to fail.
    filesystem.setFaultyRename(cacheDir / DiskLruCache.JOURNAL_FILE_BACKUP, true)
    taskFaker.runNextTask()

| Params        | Value                                          |
| :--           | :--                                            |

```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

Door `Optional[str]` te gebruiken in plaats van alleen `str`, kan de editor je helpen fouten te detecteren waarbij je ervan uit zou kunnen gaan dat een waarde altijd een `str` is, terwijl het in werkelijkheid ook `None` zou kunnen zijn.

`Optional[EenType]` is eigenlijk een snelkoppeling voor `Union[EenType, None]`, ze zijn equivalent.

  `All right,' said the Cat; and this time it vanished quite slowly,
beginning with the end of the tail, and ending with the grin,
which remained some time after the rest of it had gone.

  `Well!  I've often seen a cat without a grin,' thought Alice;
`but a grin without a cat!  It's the most curious thing I ever
saw in my life!'

  She had not gone much farther before she came in sight of the