Ein „**Callable**“ in Python ist etwas, das wie eine Funktion aufgerufen werden kann („to call“).

Wenn Sie also ein Objekt `something` haben (das möglicherweise _keine_ Funktion ist) und Sie es wie folgt aufrufen (ausführen) können:

```Python
something()
```

oder

```Python
something(some_argument, some_keyword_argument="foo")
```

dann ist das ein „Callable“ (ein „Aufrufbares“).

## Klassen als Abhängigkeiten

    assertEquals(
        "text/plain; something=\"cr@zy\"; something-else=\"crazy with spaces\";"
            + " and-another-thing=\"\"; normal-thing=foo",
        MediaType.create("text", "plain")
            .withParameter("something", "cr@zy")
            .withParameter("something-else", "crazy with spaces")
            .withParameter("and-another-thing", "")

            import ${FileCollectionFactory.name}

            class CustomTask extends DefaultTask {
                @Optional @$annotation.simpleName input
                @TaskAction void doSomething() {
                    def fileCollectionFactory = services.get(FileCollectionFactory)
                    GetInputFilesVisitor visitor = new GetInputFilesVisitor("ownerName", fileCollectionFactory)

{!../../../docs_src/python_types/tutorial009.py!}
```

⚙️ `Optional[str]` ↩️ `str` 🔜 ➡️ 👨‍🎨 ℹ 👆 🔍 ❌ 🌐❔ 👆 💪 🤔 👈 💲 🕧 `str`, 🕐❔ ⚫️ 💪 🤙 `None` 💁‍♂️.

`Optional[Something]` 🤙 ⌨ `Union[Something, None]`, 👫 🌓.

👉 ⛓ 👈 🐍 3️⃣.1️⃣0️⃣, 👆 💪 ⚙️ `Something | None`:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="1  4"
    {!> ../../../docs_src/python_types/tutorial009.py!}
    ```

	{"comment only", "{{/* comment */}}", true},
	{"definition", `{{define "x"}}something{{end}}`, true},
	{"definitions and space", "{{define `x`}}something{{end}}\n\n{{define `y`}}something{{end}}\n\n", true},
	{"definitions and text", "{{define `x`}}something{{end}}\nx\n{{define `y`}}something{{end}}\ny\n", false},
	{"definition and action", "{{define `x`}}something{{end}}{{if 3}}foo{{end}}", false},
}

func TestIsEmpty(t *testing.T) {

                File outputFile

                @Optional
                @OutputFile
                File secondaryOutputFile

                @TaskAction
                void doSomething() {
                    outputFile.text = inputFile.text
                    if (secondaryOutputFile != null) {
                        secondaryOutputFile.text = "secondary"
                    }
                }

    assertEquals(
        "text/plain; something=\"cr@zy\"; something-else=\"crazy with spaces\";"
            + " and-another-thing=\"\"; normal-thing=foo",
        MediaType.create("text", "plain")
            .withParameter("something", "cr@zy")
            .withParameter("something-else", "crazy with spaces")
            .withParameter("and-another-thing", "")

We also saw that HTTPS is normally provided by a component **external** to your application server, a **TLS Termination Proxy**.

And there has to be something in charge of **renewing the HTTPS certificates**, it could be the same component or it could be something different.

### Example Tools for HTTPS

Some of the tools you could use as a TLS Termination Proxy are:

* Traefik

`Optional[Something]` মূলত `Union[Something, None]`-এর একটি শর্টকাট, এবং তারা সমতুল্য।

এর মানে হল, Python 3.10-এ, আপনি টাইপগুলির ইউনিয়ন ঘোষণা করতে `Something | None` ব্যবহার করতে পারেন:

=== "Python 3.10+"

    ```Python hl_lines="1"
    {!> ../../../docs_src/python_types/tutorial009_py310.py!}

...but continue reading below to see how to overcome that.

## Return Type and Data Filtering

Let's continue from the previous example. We wanted to **annotate the function with one type** but return something that includes **more data**.

We want FastAPI to keep **filtering** the data using the response model.