```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

your program could execute like this:

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()
participant execute as Execute function

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

The `name` parameter is **still required** (not *optional*) because it doesn't have a default value. Still, `name` accepts `None` as the value:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

könnte Ihr Programm so ausgeführt werden:

```mermaid
sequenceDiagram

participant code as Code
participant function as say_hi()
participant execute as Funktion ausgeführt

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Camila")

       *
       * Example:
       * ```
       * --> POST /greeting http/1.1
       * Host: example.com
       * Content-Type: plain/text
       * Content-Length: 3
       *
       * Hi?
       * --> END POST
       *
       * <-- 200 OK (22ms)
       * Content-Type: plain/text
       * Content-Length: 6
       *
       * Hello!
       * <-- END HTTP
       * ```
       */

```Python
say_hi()  # Oh, nein, das löst einen Fehler aus! 😱
```

Der `name` Parameter wird **immer noch benötigt** (nicht *optional*), weil er keinen Default-Wert hat. `name` akzeptiert aber dennoch `None` als Wert:

```Python
say_hi(name=None)  # Das funktioniert, None is gültig 🎉
```

    assertThat(client.closed).isFalse()
    client.webSocket!!.close(1000, "Hi!")
    server.processNextFrame()
    client.listener.assertClosing(1000, "Hello!")
    server.listener.assertClosing(1000, "Hi!")
    client.webSocket!!.finishReader()
    server.webSocket!!.finishReader()
    client.listener.assertClosed(1000, "Hello!")
    server.listener.assertClosed(1000, "Hi!")
    taskFaker.runTasks()
    assertThat(client.closed).isTrue()

```Python
say_hi()  # ওহ না, এটি একটি ত্রুটি নিক্ষেপ করবে! 😱
```

`name` প্যারামিটারটি **এখনও আবশ্যিক** (নন-অপশনাল) কারণ এটির কোনো ডিফল্ট মান নেই। তবুও, `name` এর মান হিসেবে `None` গ্রহণযোগ্য:

```Python
say_hi(name=None)  # এটি কাজ করে, None বৈধ 🎉
```

    val request = request().post("Hi?".toRequestBody(PLAIN)).build()
    val response = client.newCall(request).execute()
    response.body.close()
    applicationLogs
      .assertLogEqual("--> POST $url")
      .assertLogEqual("Content-Type: text/plain; charset=utf-8")
      .assertLogEqual("Content-Length: 3")
      .assertLogEqual("")
      .assertLogEqual("Hi?")
      .assertLogEqual("--> END POST (3-byte body)")

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

Tham số `name` **vẫn được yêu cầu** (không phải là *tùy chọn*) vì nó không có giá trị mặc định. Trong khi đó, `name` chấp nhận `None` như là giá trị:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

{!../../../docs_src/python_types/tutorial009c.py!}
```

🔢 `name` 🔬 `Optional[str]`, ✋️ ⚫️ **🚫 📦**, 👆 🚫🔜 🤙 🔢 🍵 🔢:

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

`name` 🔢 **✔** (🚫 *📦*) ↩️ ⚫️ 🚫 ✔️ 🔢 💲. , `name` 🚫 `None` 💲:

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

👍 📰, 🕐 👆 🔛 🐍 3️⃣.1️⃣0️⃣ 👆 🏆 🚫 ✔️ 😟 🔃 👈, 👆 🔜 💪 🎯 ⚙️ `|` 🔬 🇪🇺 🆎: