HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());
    assertEquals(2, immut.size());
    assertEquals(2, mut.size());
  }

  public void testSymmetricDifference() {
    Set<String> friends = newHashSet("Tom", "Joe", "Dave");
    Set<String> enemies = newHashSet("Dick", "Harry", "Tom");

    HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());
    assertEquals(2, immut.size());
    assertEquals(2, mut.size());
  }

  public void testSymmetricDifference() {
    Set<String> friends = newHashSet("Tom", "Joe", "Dave");
    Set<String> enemies = newHashSet("Dick", "Harry", "Tom");

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note

👀 👈 ✋️ `item` 📣 🎏 🌌 ⏭, ⚫️ 🔜 ⌛ 🔘 💪 ⏮️ 🔑 `item`.

///

**FastAPI** 🔜 🏧 🛠️ ⚪️➡️ 📨, 👈 🔢 `item` 📨 ⚫️ 🎯 🎚 & 🎏 `user`.

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note | "Nota"

Repare que mesmo que o `item` esteja declarado da mesma maneira que antes, agora é esperado que ele esteja dentro do corpo com uma chave `item`.

///

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note

Notice that even though the `item` was declared the same way as before, it is now expected to be inside of the body with a key `item`.

///

            "user": {"username": "Dave"},
        },
    )
    assert response.status_code == 200
    assert response.json() == {
        "item_id": 5,
        "importance": 2,
        "item": {
            "name": "Foo",
            "price": 50.5,
            "description": None,
            "tax": None,
        },
        "user": {"username": "Dave", "full_name": None},
    }

            "user": {"username": "Dave"},
        },
    )
    assert response.status_code == 200
    assert response.json() == {
        "item_id": 5,
        "importance": 2,
        "item": {
            "name": "Foo",
            "price": 50.5,
            "description": None,
            "tax": None,
        },
        "user": {"username": "Dave", "full_name": None},
    }


@needs_py310

            "user": {"username": "Dave"},
        },
    )
    assert response.status_code == 200
    assert response.json() == {
        "item_id": 5,
        "importance": 2,
        "item": {
            "name": "Foo",
            "price": 50.5,
            "description": None,
            "tax": None,
        },
        "user": {"username": "Dave", "full_name": None},
    }


@needs_py39

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note | "Hinweis"

Beachten Sie, dass, obwohl `item` wie zuvor deklariert wurde, es nun unter einem Schlüssel `item` im Body erwartet wird.

///

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}
```

/// note | "참고"

이전과 같이 `item`이 선언 되었더라도, 본문 내의 `item` 키가 있을 것이라고 예측합니다.

///

FastAPI는 요청을 자동으로 변환해, 매개변수의 `item`과 `user`를 특별한 내용으로 받도록 할 것입니다.