*
     * @return an {@link Optional} containing the map of user properties, or empty if not set
     */
    @Nonnull
    Optional<Map<String, String>> userProperties();

    /**
     * Indicates whether to show the version information and exit.
     *
     * @return an {@link Optional} containing the boolean flag, or empty if not set
     */
    @Nonnull
    Optional<Boolean> showVersionAndExit();

    /**

    )


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_missing(path: str):
    client = TestClient(app)
    response = client.get(path)
    assert response.status_code == 200
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str(path: str):

@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str_missing(path: str):
    client = TestClient(app)
    response = client.get(path)
    assert response.status_code == 200, response.text
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)

    protected LayeredMavenOptions(List<O> options) {
        super(options);
    }

    @Override
    public Optional<String> alternatePomFile() {
        return returnFirstPresentOrEmpty(MavenOptions::alternatePomFile);
    }

    @Override
    public Optional<Boolean> nonRecursive() {
        return returnFirstPresentOrEmpty(MavenOptions::nonRecursive);
    }

    @Override
    public Optional<Boolean> updateSnapshots() {

    )


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_missing(path: str):
    client = TestClient(app)
    response = client.get(path)
    assert response.status_code == 200
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str(path: str):

Here's a tip from my very **subjective** point of view:

* 🚨 Avoid using `Optional[SomeType]`
* Instead ✨ **use `Union[SomeType, None]`** ✨.

兩者等價且底層相同，但我會推薦用 `Union` 而不要用 `Optional`，因為「optional」這個詞看起來會讓人以為這個值是可選的，但實際上它的意思是「可以是 `None`」，即使它不是可選的、仍然是必填。

我認為 `Union[SomeType, None]` 更能清楚表達其含義。

這只是措辭與命名問題，但這些詞會影響你與團隊成員對程式碼的理解。

例如，看看下面這個函式：

```python
from typing import Optional


def say_hi(name: Optional[str]):
    print(f"Hey {name}!")
```

參數 `name` 被標註為 `Optional[str]`，但它並不是可選的；你不能在沒有該參數的情況下呼叫這個函式：

```Python

    )


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_missing(path: str):
    client = TestClient(app)
    response = client.get(path)
    assert response.status_code == 200
    assert response.json() == {"p": None}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str(path: str):

			Optional:    true,
			Type:        "string",
			Sensitive:   false,
		},
		config.HelpKV{
			Key:         LookupBindDN,
			Description: `DN for LDAP read-only service account used to perform DN and group lookups` + defaultHelpPostfix(LookupBindDN),
			Optional:    true,
			Type:        "string",
			Sensitive:   true,
		},
		config.HelpKV{

import java.util.List;
import java.util.Optional;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.cli.Options;

/**
 * Defines the options specific to Maven operations.
 * This interface extends the general {@link Options} interface, adding Maven-specific configuration options.
 *