Não faz diferença. O **FastAPI** sabe o que fazer.

/// note | Nota

Caso você não conheça, veja em [Async: *"Com Pressa?"*](../../async.md#in-a-hurry){.internal-link target=_blank} a sessão acerca de `async` e `await` na documentação.

///

## Integrando com OpenAPI { #integrated-with-openapi }

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>또는 <code>async def</code> 사용하기...</summary>

여러분의 코드가 `async` / `await`을 사용한다면, `async def`를 사용하십시오.

```Python hl_lines="9 14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

	dataUsageCacheVerV4      = 4
	dataUsageCacheVerV3      = 3
	dataUsageCacheVerV2      = 2
	dataUsageCacheVerV1      = 1
)

// serialize the contents of the cache.
func (d *dataUsageCache) serializeTo(dst io.Writer) error {
	// Add version and compress.
	_, err := dst.Write([]byte{dataUsageCacheVerCurrent})
	if err != nil {
		return err
	}
	enc, err := zstd.NewWriter(dst,
		zstd.WithEncoderLevel(zstd.SpeedFastest),

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

	// the connection will be closed and readers/writers will unblock.
	go c.monitorState(conn, cancel)

	c.handleMsgWg.Add(2)
	c.reconnectMu.Unlock()

	// Start reader and writer
	go c.readStream(ctx, conn, cancel)
	c.writeStream(ctx, conn, cancel)
}

// readStream handles the read side of the connection.
// It will read messages and send them to c.handleMsg.

            </execution>
            <execution>
              <id>standard</id>
              <goals>
                <goal>java</goal>
                <goal>xpp3-reader</goal>
                <goal>xpp3-writer</goal>
              </goals>
            </execution>
          </executions>
        </plugin>
        <plugin>
          <groupId>org.apache.felix</groupId>

java.util.Map optionsByString; private boolean allowMixedOptions; private boolean allowUnknownOptions; private final java.io.PrintWriter deprecationPrinter; static void <clinit>(); public void CommandLineParser(); public void CommandLineParser(java.io.Writer); public transient ParsedCommandLine parse(String[]) throws CommandLineArgumentE; public ParsedCommandLine parse(Iterable) throws CommandLineArgumentE; public CommandLineParser allowMixedSubcommand(); public CommandLineParser allowUnknownOptions();...

                } finally {
                    latch.countDown();
                }
            });
        }

        latch.await(5, TimeUnit.SECONDS);
        executor.shutdown();

        // Verify all listeners were added
        assertEquals(numThreads, fesenClient.onConnectListenerList.size());
    }

    /**

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

pkg log/syslog (darwin-arm64), method (*Writer) Emerg(string) error
pkg log/syslog (darwin-arm64), method (*Writer) Err(string) error
pkg log/syslog (darwin-arm64), method (*Writer) Info(string) error
pkg log/syslog (darwin-arm64), method (*Writer) Notice(string) error
pkg log/syslog (darwin-arm64), method (*Writer) Warning(string) error
pkg log/syslog (darwin-arm64), method (*Writer) Write([]uint8) (int, error)