Sie wird von **FastAPI** immer dann aufgerufen, wenn sie eine Anfrage an die URL "`/`" mittels einer `GET`-Operation erhält.

In diesem Fall handelt es sich um eine `async`-Funktion.

---

Sie könnten sie auch als normale Funktion anstelle von `async def` definieren:

```Python hl_lines="7"
{!../../docs_src/first_steps/tutorial003.py!}
```

/// note | "Hinweis"

| *Valid Range* | *Minimum value of 900. Maximum value of 31536000.* |
| *Required*    | *No*                                               |

### Policy

import org.apache.maven.model.v4.MavenStaxReader;
import org.codehaus.plexus.util.xml.XmlStreamWriter;

/**
 * Handles deserialization of a model from some kind of textual format like XML.
 *
 * @deprecated use {@link XmlStreamWriter} instead
 */
@Named
@Singleton
@Deprecated(since = "4.0.0")
public class DefaultModelReader implements ModelReader {

  JAVA_SPECIFICATION_VENDOR("java.specification.vendor"),

  /** Java Runtime Environment specification name. */
  JAVA_SPECIFICATION_NAME("java.specification.name"),

  /** Java class format version number. */
  JAVA_CLASS_VERSION("java.class.version"),

  /** Java class path. */
  JAVA_CLASS_PATH("java.class.path"),

  /** List of paths to search when loading libraries. */

### `HTTPException` importieren

```Python hl_lines="1"
{!../../docs_src/handling_errors/tutorial001.py!}
```

### Eine `HTTPException` in Ihrem Code auslösen

`HTTPException` ist eine normale Python-<abbr title="Exception – Ausnahme, Fehler: Python-Objekt, das einen Fehler nebst Metadaten repräsentiert">Exception</abbr> mit einigen zusätzlichen Daten, die für APIs relevant sind.

		// as the peer might be coming up and trying to read format.json
		// or create format.json
		return true
	}

	storedDiskID, err := s.getStorage().GetDiskID()
	if err != nil {
		s.writeErrorResponse(w, err)
		return false
	}

	if diskID != storedDiskID {
		s.writeErrorResponse(w, errDiskStale)
		return false
	}

    If you feel the source code should be reformatted, create a separate PR for this change.
  + Check for unnecessary whitespace with `git diff --check` before committing.
+ Make sure your commit messages are in the proper format. Your commit message should contain the key of the JIRA issue.
```
[MNG-XXX] - Subject of the JIRA Ticket
 Optional supplemental description.
```

        if (StringUtil.isBlank(options.sessionId)) {
            // use a default session id
            final SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
            options.sessionId = sdf.format(new Date());
        } else {
            options.sessionId = options.sessionId.replace('-', '_');
        }

        final CrawlingInfoHelper crawlingInfoHelper = ComponentUtil.getCrawlingInfoHelper();

        if (sources == null) {
            return null;
        }
        return sources.stream()
                .reduce((a, b) -> {
                    throw new IllegalStateException(String.format(
                            "No unique Source for %s:%s: %s and %s",
                            groupId, artifactId, a.getLocation(), b.getLocation()));
                })
                .orElse(null);
    }

			switch len(s) {
			case 1:
				// nothing to do
			case 2:
				if p, err := strconv.Atoi(s[1]); err == nil {
					parts = p
				} else {
					log.Println("FAILED: ETAG of", objFullPath(object), "has a wrong format:", err)
					continue
				}
				multipart = true
			default:
				log.Println("FAILED: Unexpected ETAG", object.ETag, "for object:", objFullPath(object))
				continue
			}

			var partsMD5Sum [][]byte