## Caveat

If you need to perform heavy background computation and you don't necessarily need it to be run by the same process (for example, you don't need to share memory, variables, etc), you might benefit from using other bigger tools like <a href="https://docs.celeryq.dev" class="external-link" target="_blank">Celery</a>.

```Python hl_lines="3  5"
{!../../docs_src/dependencies/tutorial007.py!}
```

## Sub-dependencies with `yield`

You can have sub-dependencies and "trees" of sub-dependencies of any size and shape, and any or all of them can use `yield`.

**FastAPI** will make sure that the "exit code" in each dependency with `yield` is run in the correct order.

(And, as you might like to try the thing yourself, some winter
day, I will tell you how the Dodo managed it.)

  First it marked out a race-course, in a sort of circle, (`the
exact shape doesn't matter,' it said,) and then all the party
were placed along the course, here and there.  There was no `One,
two, three, and away,' but they began running when they liked,

	quiet(msg string, args ...interface{})
	pretty(msg string, args ...interface{})
}

func consoleLog(console Logger, msg string, args ...interface{}) {
	switch {
	case jsonFlag:
		// Strip escape control characters from json message
		msg = ansiRE.ReplaceAllLiteralString(msg, "")
		console.json(msg, args...)
	case quietFlag:
		if len(msg) != 0 && len(args) == 0 {
			args = append(args, msg)
			msg = "%s"
		}

@endlocal & set MAVEN_OPTS=%MAVEN_OPTS% %JVM_CONFIG_MAVEN_OPTS%

:endReadJvmConfig

@REM do not let MAVEN_PROJECTBASEDIR end with a single backslash which would escape the double quote. This happens when .mvn at drive root.
if "_%MAVEN_PROJECTBASEDIR:~-1%"=="_\" set "MAVEN_PROJECTBASEDIR=%MAVEN_PROJECTBASEDIR%\"

if "%MAVEN_DEBUG_ADDRESS%"=="" set MAVEN_DEBUG_ADDRESS=localhost:8000

            if (logger.isDebugEnabled()) {
                logger.debug("Invalid query: {}", query, e);
            }
            query = ComponentUtil.getQueryStringBuilder().params(params).sortField(params.getSort()).escape(true).build();
            documentItems = searchInternal(query, params, userBean);
        }

        data.setDocumentItems(documentItems);

        // search

<img src="/img/python-types/image06.png">

## Pydantic 모델

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a>은 데이터 검증(Validation)을 위한 파이썬 라이브러리입니다.

당신은 속성들을 포함한 클래스 형태로 "모양(shape)"을 선언할 수 있습니다.

그리고 각 속성은 타입을 가지고 있습니다.

이 클래스를 활용하여서 값을 가지고 있는 인스턴스를 만들게 되면, 필요한 경우에는 적당한 타입으로 변환까지 시키기도 하여 데이터가 포함된 객체를 반환합니다.

그리고 결과 객체에 대해서는 에디터의 도움을 받을 수 있게 됩니다.

Pydantic 공식 문서 예시:

   * The maximum number of requests for each host to execute concurrently. This limits requests by
   * the URL's host name. Note that concurrent requests to a single IP address may still exceed this
   * limit: multiple hostnames may share an IP address or be routed through the same HTTP proxy.
   *
   * If more than [maxRequestsPerHost] requests are in flight when this is invoked, those requests
   * will remain in flight.
   *

			if err != nil {
				fmt.Fprintf(os.Stdout, "set flag %q as true failed due to error %v", flag.Name, err)
			}
		}
	})
	return versionCmd
}

// xdsRemoteVersionWrapper uses outXDS to share the XDS response with xdsProxyVersionWrapper.
// (Screwy API on istioVersion.CobraCommandWithOptions)
// nolint: lll

	signature := formValues.Get(xhttp.AmzSignatureV2)
	if !compareSignatureV2(signature, calculateSignatureV2(policy, cred.SecretKey)) {
		return cred, ErrSignatureDoesNotMatch
	}
	return cred, ErrNone
}

// Escape encodedQuery string into unescaped list of query params, returns error
// if any while unescaping the values.
func unescapeQueries(encodedQuery string) (unescapedQueries []string, err error) {