#### `Optional`

`str`과 같이 타입을 선언할 때 `Optional`을 쓸 수도 있는데, "선택적(Optional)"이기때문에 `None`도 될 수 있습니다:

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

`Optional[str]`을 `str` 대신 쓰게 되면, 특정 값이 실제로는 `None`이 될 수도 있는데 항상 `str`이라고 가정하는 상황에서 에디터가 에러를 찾게 도와줄 수 있습니다.

#### Generic(제네릭) 타입

이 타입은 대괄호 안에 매개변수를 가지며, 종류는:

* `List`
* `Tuple`
* `Set`
* `Dict`

sleep 5

# Generate STS credential with STS call to minio1
STS_CRED=$(MINIO_ENDPOINT=http://localhost:9001 go run ./docs/site-replication/gen-oidc-sts-cred.go)

MC_HOST_foo=http://${STS_CRED}@localhost:9001 ./mc ls foo
if [ $? -ne 0 ]; then
	echo "Expected sts credential to work, exiting.."
	exit_1
fi

sleep 2

# Check that the STS credential works on minio2 and minio3.

        assertEquals(FileInformation.FILE_ENDOFFILE_INFO, fileInfoWithEof.getFileInformationLevel());

        // Test toString
        String str = fileInfoWithEof.toString();
        assertNotNull(str);
        assertTrue(str.contains("EndOfFileInformation"));
        assertTrue(str.contains("1024"));
    }

    /**
     * Test FileEndOfFileInformation encode/decode round trip
     */
    @Test

| policy     | _string_       | Canned policy name to be applied for STS credentials. (Recommended)                                                                                                                     |

En este ejemplo, convertiría el modelo de Pydantic a un `dict`, y el `datetime` a un `str`.

El resultado de llamarlo es algo que puede ser codificado con la función estándar de Python <a href="https://docs.python.org/3/library/json.html#json.dumps" class="external-link" target="_blank">`json.dumps()`</a>.

from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


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


@app.put("/items/{item_id}")

, `datetime` 🎚 🔜 ✔️ 🗜 `str` ⚗ 💽 <a href="https://en.wikipedia.org/wiki/ISO_8601" class="external-link" target="_blank">💾 📁</a>.

🎏 🌌, 👉 💽 🚫🔜 📨 Pydantic 🏷 (🎚 ⏮️ 🔢), 🕴 `dict`.

👆 💪 ⚙️ `jsonable_encoder` 👈.

⚫️ 📨 🎚, 💖 Pydantic 🏷, &amp; 📨 🎻 🔗 ⏬:

{* ../../docs_src/encoder/tutorial001.py hl[5,22] *}

👉 🖼, ⚫️ 🔜 🗜 Pydantic 🏷 `dict`, &amp; `datetime` `str`.

///

## ⚫️❔ ⚫️ 🔨

⚫️ 🔜 🚶 & 👀 📨 👈 `Authorization` 🎚, ✅ 🚥 💲 `Bearer ` ➕ 🤝, & 🔜 📨 🤝 `str`.

🚥 ⚫️ 🚫 👀 `Authorization` 🎚, ⚖️ 💲 🚫 ✔️ `Bearer ` 🤝, ⚫️ 🔜 📨 ⏮️ 4️⃣0️⃣1️⃣ 👔 📟 ❌ (`UNAUTHORIZED`) 🔗.

👆 🚫 ✔️ ✅ 🚥 🤝 🔀 📨 ❌. 👆 💪 💭 👈 🚥 👆 🔢 🛠️, ⚫️ 🔜 ✔️ `str` 👈 🤝.

👆 💪 🔄 ⚫️ ⏪ 🎓 🩺:

<img src="/img/tutorial/security/image03.png">

👥 🚫 ✔ 🔬 🤝, ✋️ 👈 ▶️ ⏪.

        SmbComNTCreateAndX req = createRequest(0, 0);
        String str = req.toString();
        assertTrue(str.startsWith("SmbComNTCreateAndX["), "toString should start with class name");
        assertTrue(str.contains("name=test.txt"), "The file name should appear");
        // securityFlags are set to 0x03 – verify hex sequence
        assertTrue(str.contains("securityFlags=0x03"), "securityFlags should be present");
    }

    }

    @Test
    void testToString() {
        NetworkInterfaceInfo info = new NetworkInterfaceInfo(testAddress, 1000);
        String str = info.toString();

        assertNotNull(str);
        assertTrue(str.contains(testAddress.toString()));
        assertTrue(str.contains("1000"));
    }