```Python
from typing import Union
from fastapi import Cookie, FastAPI, Header, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
def main(
    item_id: int = Path(gt=0),
    query: Union[str, None] = Query(default=None, max_length=10),
    session: Union[str, None] = Cookie(default=None, min_length=3),

```

/// tip | 팁

<a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 의 두 번째 인자는 반환할 기본값입니다.

여기서는 `"World"`를 넣었기에 기본값으로써 사용됩니다. 넣지 않으면 `None` 이 기본값으로 사용됩니다.

///

그러면 해당 파이썬 프로그램을 다음과 같이 호출할 수 있습니다:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// Here we don't set the env var yet
$ python main.py

            } else {
                filePrefix = name;
                extention = "";
            }
            filePrefix = filePrefix.replaceAll("\\p{Zs}", "_");
        } else {
            filePrefix = "none";
            extention = "";
        }
        File inputFile = null;
        File outputFile = null;
        try {
            inputFile =

     * This method manages local caches and fetches from OpenSearch when needed.
     *
     * @param sessionId The session ID.
     * @return The next URL queue entry, or null if none available.
     */
    @Override
    public OpenSearchUrlQueue poll(final String sessionId) {
        final QueueHolder queueHolder = getQueueHolder(sessionId);

      "scheduledTasks=[task two, task one]",
    )

    taskFaker.advanceUntil(200.µs)
    assertThat(log).containsExactly(
      "scheduledTasks=[task two, task one]",
      "scheduledTasks=[task one]",
    )

    taskFaker.advanceUntil(300.µs)
    assertThat(log).containsExactly(
      "scheduledTasks=[task two, task one]",
      "scheduledTasks=[task one]",
      "scheduledTasks=[]",
    )

from fastapi import FastAPI

app = FastAPI()


@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}
```

### Dockerfile

Ahora, en el mismo directorio del proyecto, crea un archivo `Dockerfile` con:

```{ .dockerfile .annotate }
# (1)!

print(f"Hello {name} from Python")
```

/// tip

第二個參數是 <a href="https://docs.python.org/zh-tw/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 的預設回傳值。

如果沒有提供，預設值為 `None`，這裡我們提供 `"World"` 作為預設值。

///

然後你可以呼叫這個 Python 程式：

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// 這裡我們還沒有設定環境變數
$ python main.py

// 因為我們沒有設定環境變數，所以我們得到的是預設值

			return true
		}
	}

	// None found return false, perhaps entry removed in previous run.
	return false
}

func (l *localLocker) RLock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	if len(args.Resources) != 1 {
		return false, fmt.Errorf("internal error: localLocker.RLock called with more than one resource")
	}
	// If we have too many waiting, reject this at once.

 *   <li>useEPSVwithIPv4: Whether to use EPSV with IPv4.</li>
 *   <li>isImplicit: Whether to use implicit SSL/TLS encryption.</li>
 *   <li>trustManager: The trust manager to use for SSL/TLS connections ("all", "valid", or "none").</li>
 *   <li>enterLocalPassiveMode: Whether to enter local passive mode.</li>
 *   <li>ftpAuthentications: An array of {@link FtpAuthentication} objects for different FTP URLs.</li>
 * </ul>
 *
 * <p>

  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Float> none = Arrays.<Float>asList();
    assertThat(Floats.toArray(none)).isEqualTo(EMPTY);

    List<Float> one = Arrays.asList(1.0f);
    assertThat(Floats.toArray(one)).isEqualTo(ARRAY1);

    float[] array = {0.0f, 1.0f, 3.0f};

    List<Float> three = Arrays.asList(0.0f, 1.0f, 3.0f);