t.Fatal(err)
	}
	hdr, err := FileInfoHeader(fileinfo, "")
	if err != nil {
		t.Fatalf("os.Stat: %v", err)
	}
	contents := strings.Repeat(" ", int(hdr.Size))

	hdr.Xattrs = map[string]string{
		"foo": "foo",
		"bar": "bar",
		"baz": "baz",
		"qux": "qux",
	}

	var buf bytes.Buffer
	writer := NewWriter(&buf)
	if err := writer.WriteHeader(hdr); err != nil {
		t.Fatal(err)
	}

  }

  public void testAsSet_absentIsImmutable() {
    Set<Object> absentAsSet = Optional.absent().asSet();
    assertThrows(UnsupportedOperationException.class, () -> absentAsSet.add("foo"));
  }

  public void testTransform_absent() {
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));

```Python
something()
```

oder

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

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

## Klassen als Abhängigkeiten { #classes-as-dependencies_1 }

在 Python 中，「**callable**」指的是任何可以像函式一樣被 Python「呼叫」的東西。

因此，如果你有一個物件 `something`（它可能不是函式），而你可以像這樣「呼叫」（執行）它：

```Python
something()
```

或是

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

那它就是一個「callable」。

## 以類別作為相依性 { #classes-as-dependencies_1 }

你可能已經注意到，建立一個 Python 類別的實例時，你用的語法也是一樣的。

例如：

```Python
class Cat:
    def __init__(self, name: str):

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

TEXT errors(SB),$0
	MOVL	foo<>(SB)(AX), AX	// ERROR "invalid instruction"
	MOVL	(AX)(SP*1), AX		// ERROR "invalid instruction"
	EXTRACTPS $4, X2, (BX)          // ERROR "invalid instruction"
	EXTRACTPS $-1, X2, (BX)         // ERROR "invalid instruction"
	// VSIB addressing does not permit non-vector (X/Y)

 * </ul>
 *
 * <h4>Example usage</h4>
 *
 * {@snippet :
 * class Foo {
 *   private static final ImmutableSet<String> RESERVED_CODES =
 *       ImmutableSet.of("AZ", "CQ", "ZX");
 *
 *   private final ImmutableSet<String> codes;
 *
 *   public Foo(Iterable<String> codes) {
 *     this.codes = ImmutableSet.copyOf(codes);

Ainsi, si vous envoyez une requête à ce *chemin d'accès* pour l'article avec l'ID `foo`, la réponse (sans les valeurs par défaut) sera :

```JSON
{
    "name": "Foo",
    "price": 50.2
}
```

/// info | Info

Vous pouvez également utiliser :

* `response_model_exclude_defaults=True`

	DB.Migrator().DropTable(&LevelA3{}, &LevelA2{}, &LevelA1{})
	if err := DB.AutoMigrate(&LevelA1{}, &LevelA2{}, &LevelA3{}); err != nil {
		t.Error(err)
	}

	levelA1 := &LevelA1{Value: "foo"}
	if err := DB.Save(levelA1).Error; err != nil {
		t.Error(err)
	}

	want := []*LevelA2{
		{
			Value: "bar",
			LevelA3s: []*LevelA3{
				{
					Value:   "qux",
					LevelA1: levelA1,

				}
			}
		}
	}
}

var indexTests = []BinOpTest{
	{"", "", 0},
	{"", "a", -1},
	{"", "foo", -1},
	{"fo", "foo", -1},
	{"foo", "baz", -1},
	{"foo", "foo", 0},
	{"oofofoofooo", "f", 2},
	{"oofofoofooo", "foo", 4},
	{"barfoobarfoo", "foo", 3},
	{"foo", "", 0},
	{"foo", "o", 1},
	{"abcABCabc", "A", 3},
	// cases with one byte strings - test IndexByte and special case in Index()

    }

    protected ArtifactRepository badRemoteRepository() throws Exception {
        return artifactRepositoryFactory.createArtifactRepository(
                "test", "http://foo.bar/repository", repoLayout, null, null);
    }

    protected void assertRemoteArtifactPresent(Artifact artifact) throws Exception {
        ArtifactRepository remoteRepo = remoteRepository();