@Override public EventListener create(Call call) {
      if (Math.random() < 0.10) {
        return new MetricsEventListener(call);
      } else {
        return EventListener.NONE;
      }
    }
  };

  ...
}
```

### Events with Failures

Wenn Sie jedoch eine benutzerdefinierte Response-Klasse mit `None` als Medientyp angegeben haben, verwendet FastAPI `application/json` für jede zusätzliche Response, die über ein zugehöriges Modell verfügt.

///

## Informationen kombinieren

But if you have specified a custom response class with `None` as its media type, FastAPI will use `application/json` for any additional response that has an associated model.

///

## Combining information

each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form. 3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as...

    client.listener.assertClosing(1000, "Bye!")
  }

  @Test
  fun protocolErrorBeforeCloseSendsFailure() {
    server.sink.write("0a00".decodeHex()).emit() // Invalid non-final ping frame.
    client.processNextFrame() // Detects error, send close, close connection.
    taskFaker.runTasks()
    client.webSocket!!.finishReader()
    assertThat(client.closed).isTrue()

		// Some systems use leading _ to denote non-assembly symbols.
		return s == "__cgodebug_ints" || s == "___cgodebug_ints"
	}
	isDebugFloats := func(s string) bool {
		// Some systems use leading _ to denote non-assembly symbols.
		return s == "__cgodebug_floats" || s == "___cgodebug_floats"
	}
	indexOfDebugStr := func(s string) int {
		// Some systems use leading _ to denote non-assembly symbols.

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

Now in the same project directory create a file `Dockerfile` with:

```{ .dockerfile .annotate }
# (1)!
FROM python:3.9

   * href="http://www.ietf.org/rfc/rfc1035.txt">RFC 1035</a> is relaxed in the following ways:
   *
   * <ul>
   *   <li>Any part containing non-ASCII characters is considered valid.
   *   <li>Underscores ('_') are permitted wherever dashes ('-') are permitted.
   *   <li>Parts other than the final part may start with a digit, as mandated by <a

     *
     * @return an {@link Optional} containing the fail-on-severity string, or empty if not set
     */
    @Nonnull
    Optional<String> failOnSeverity();

    /**
     * Indicates whether to run in non-interactive mode.
     *
     * @return an {@link Optional} containing the boolean flag, or empty if not set
     */
    @Nonnull
    Optional<Boolean> nonInteractive();

    /**

      // surrogate range. Either way the character range is empty.
      this.safeMinChar = Character.MAX_VALUE;
      this.safeMaxChar = 0;
    } else {
      // The safe range is non-empty and contains values below the surrogate
      // range but may extend above it. We may need to clip the maximum value.
      this.safeMinChar = (char) safeMin;