* `read(anzahl)`: Liest `anzahl` (`int`) bytes/Zeichen aus der Datei.
* `seek(versatz)`: Geht zur Position `versatz` (`int`) in der Datei.
    * Z. B. würde `await myfile.seek(0)` zum Anfang der Datei gehen.
    * Das ist besonders dann nützlich, wenn Sie `await myfile.read()` einmal ausführen und dann diese Inhalte erneut auslesen müssen.
* `close()`: Schließt die Datei.

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

But that's not the only way to declare dependencies (although it would probably be the more common).

The key factor is that a dependency should be a "callable".

		case <-m.ctx.Done():
			return
		case <-t.C:
			last := time.Since(time.Unix(atomic.LoadInt64(&m.LastPing), 0))
			if last > 4*m.clientPingInterval {
				gridLogIf(m.ctx, fmt.Errorf("canceling remote connection %s not seen for %v", m.parent, last))
				m.close()
				return
			}
		}
	}
}

// checkSeq will check if sequence number is correct and increment it by 1.
func (m *muxServer) checkSeq(seq uint32) (ok bool) {

There is no cancellation propagation for single payload requests.
When the context is canceled, the request will return at once with an appropriate error.
However, the remote call will not see the cancellation - as can be seen from the 'missing' context on the handler.
The result will be discarded.

### Typed handlers

Typed handlers are handlers that have a specific type for the request and response payloads.

{* ../../docs_src/path_operation_advanced_configuration/tutorial004_py310.py hl[17:27] *}

## Additional Responses { #additional-responses }

You probably have seen how to declare the `response_model` and `status_code` for a *path operation*.

That defines the metadata about the main response of a *path operation*.

        if ((createOptions & 0x0001) == 0) {
            this.createOptions = createOptions | 0x0040;
        } else {
            this.createOptions = createOptions;
        }
        this.impersonationLevel = 0x02; // As seen on NT :~)
        this.securityFlags = (byte) 0x03; // SECURITY_CONTEXT_TRACKING | SECURITY_EFFECTIVE_ONLY
    }

    /**
     * {@inheritDoc}
     *

# Advanced Dependencies { #advanced-dependencies }

## Parameterized dependencies { #parameterized-dependencies }

All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

practice is to set conventions in a plugin (2). This keeps the underlying object "dumb", so it can be reused in multiple contexts and doesn't contain any special information about how conventions are calculated or what they could be.  In the wild, we've seen some objects set conventions in the object's constructor (3), but this can lead to unexpected assumptions or coupling between plugins.

For external plugins, it's difficult for an object to be used outside the application of a plugin, so...

Der Exceptionhandler erhält einen `Request` und die Exception.

{* ../../docs_src/handling_errors/tutorial004_py39.py hl[2,14:19] *}

Wenn Sie nun zu `/items/foo` gehen, erhalten Sie anstelle des standardmäßigen JSON-Fehlers mit:

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],

  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be
  // seen as fields of an imaginary `Entry` object like this:
  //
  // class Entry {
  //    int hash;
  //    Entry next;
  //    K key;
  //    V value;
  // }
  //