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

### Dockerfile

Agora, no mesmo diretório do projeto, crie um arquivo `Dockerfile` com:

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

# (2)
WORKDIR /code

# (3)
COPY ./requirements.txt /code/requirements.txt

# (4)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# (5)

    return {"item_id": item_id, "q": q}
```

### Dockerfile

Erstellen Sie nun im selben Projektverzeichnis eine Datei `Dockerfile` mit:

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

# (2)
WORKDIR /code

# (3)
COPY ./requirements.txt /code/requirements.txt

# (4)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# (5)

Das umfasst viele Bibliotheken zur Interaktion mit Cloud-Speicher, Videoverarbeitung und anderen.

```{ .python .annotate hl_lines="2  10-12  14" }
{!../../docs_src/custom_response/tutorial008.py!}
```

1. Das ist die Generatorfunktion. Es handelt sich um eine „Generatorfunktion“, da sie `yield`-Anweisungen enthält.

			// then assume this event was generated by the CNI plugin labeling the pod on startup,
			// and skip the event.
			//
			// This isn't perfect (someone could manually annotate an unready pod,
			// then install Istio, then the pod goes ready, and we'd miss capture) - but that
			// seems vanishingly unlikely
			wasReady := kube.CheckPodReadyOrComplete(oldPod)

This includes many libraries to interact with cloud storage, video processing, and others.

```{ .python .annotate hl_lines="2  10-12  14" }
{!../../docs_src/custom_response/tutorial008.py!}
```

1. This is the generator function. It's a "generator function" because it contains `yield` statements inside.

* Create unit tests using [Spock](https://spockframework.org/spock/docs/2.0/index.html) for new classes or methods that you introduce.
* Create integration tests that exercise a Gradle build for the bug/feature. 
* Annotate tests that correspond to a bug on GitHub (`@Issue("https://github.com/gradle/gradle/issues/2622")`).

@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

### Dockerfile

现在在相同的project目录创建一个名为`Dockerfile`的文件:

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

# (2)
WORKDIR /code

# (3)
COPY ./requirements.txt /code/requirements.txt

# (4)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# (5)

    /*
     * Don't bother testing: Preconditions defines a bunch of methods that accept a template (or
     * even entire message) that simultaneously:
     *
     * - _shouldn't_ be null, so we don't annotate it with @Nullable
     *
     * - _can_ be null without causing a runtime failure (because we don't want the interesting
     *   details of precondition failure to be hidden by an exception we throw about an unexpectedly

In an expression switch, the cases contain expressions that are compared
against the value of the switch expression.
In a type switch, the cases contain types that are compared against the
type of a specially annotated switch expression.
The switch expression is evaluated exactly once in a switch statement.
</p>

<h4 id="Expression_switches">Expression switches</h4>

<p>
In an expression switch,

Isso inclui muitas bibliotecas que interagem com armazenamento em nuvem, processamento de vídeos, entre outras.

```{ .python .annotate hl_lines="2  10-12  14" }
{!../../docs_src/custom_response/tutorial008.py!}
```

1. Essa é a função geradora. É definida como "função geradora" porque contém declarações `yield` nela.