* Normally used as a C string terminator.
   *
   * <p>Although RFC 20 names this as "Null", note that it is distinct from the C/C++ "NULL"
   * pointer.
   *
   * @since 8.0
   */
  public static final byte NUL = 0;

  /**
   * Start of Heading: A communication control character used at the beginning of a sequence of

### **4.1 Spark Pi**

Test the Spark installation by running the following compute intensive example, which calculates pi by “throwing darts” at a circle. The program generates points in the unit square ((0,0) to (1,1)) and counts how many points fall within the unit circle within the square. The result approximates pi.

Follow these steps to run the Spark Pi example:

- Login as user **‘spark’**.

			errMsg = "The provided heal sequence path overlaps with an existing " +
				fmt.Sprintf("heal path: %s", k)
			return nil, errorCodes.ToAPIErr(ErrHealOverlappingPaths), errMsg
		}
	}

	// Add heal state and start sequence
	ahs.healSeqMap[hpath] = h

	clientToken := h.clientToken
	if globalIsDistErasure {
		clientToken = fmt.Sprintf("%s%s%d", h.clientToken, getKeySeparator(), GetProxyEndpointLocalIndex(globalProxyEndpoints))

  /**
   * Tests that the method {@code putEdge} will silently add the missing nodes to the graph, then
   * add the edge connecting them. We are not using the proxy methods here as we want to test {@code
   * putEdge} when the end-points are not elements of the graph.
   */
  @Test
  public void putEdge_nodesNotInGraph() {
    assume().that(graphIsMutable()).isTrue();

    graphAsMutableGraph.addNode(N1);

	t := UTCNow()
	// Add the expiration date.
	expirationStr := fmt.Sprintf(`"expiration": "%s"`, expiration.Format(iso8601TimeFormat))
	// Add the bucket condition, only accept buckets equal to the one passed.
	bucketConditionStr := fmt.Sprintf(`["eq", "$bucket", "%s"]`, bucketName)
	// Add the key condition, only accept keys equal to the one passed.
	keyConditionStr := fmt.Sprintf(`["eq", "$key", "%s/upload.txt"]`, objectKey)

e depois chamarmos:

```Python
user_dict = user_in.dict()
```

agora temos um `dict` com os dados na variável `user_dict` (é um `dict` em vez de um objeto de modelo Pydantic).

E se chamarmos:

```Python
print(user_dict)
```

teríamos um `dict` Python com:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': '******@****.***',
    'full_name': None,
}
```

```Python
user_dict = user_in.dict()
```

то теперь у нас есть `dict` с данными модели в переменной `user_dict` (это `dict` вместо объекта Pydantic-модели).

И если мы вызовем:

```Python
print(user_dict)
```

мы можем получить `dict` с такими данными:

```Python
{
    'username': 'john',
    'password': 'secret',
    'email': '******@****.***',
    'full_name': None,
}
```

Por ejemplo, aunque `users` iría después de `items` en orden alfabético, se muestra antes porque agregamos su metadata como el primer diccionario en la list.

## URL de OpenAPI

Por defecto, el esquema OpenAPI se sirve en `/openapi.json`.

Pero puedes configurarlo con el parámetro `openapi_url`.

## 파이썬에서 환경 변수 읽기

파이썬 **바깥**인 터미널에서(다른 도구로도 가능) 환경 변수를 생성도 할 수도 있고, 이를 **파이썬에서 읽을 수 있습니다.**

예를 들어 다음과 같은 `main.py` 파일이 있다고 합시다:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

/// 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.

    return new Builder();
  }

  /**
   * A builder for simple, fast escapers.
   *
   * <p>Typically an escaper needs to deal with the escaping of high valued characters or code
   * points. In these cases it is necessary to extend either {@link ArrayBasedCharEscaper} or {@link
   * ArrayBasedUnicodeEscaper} to provide the desired behavior. However this builder is suitable for