{* ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py hl[10] *}

/// note

A path parameter is always required as it has to be part of the path. Even if you declared it with `None` or set a default value, it would not affect anything, it would still be always required.

///

## Order the parameters as you need { #order-the-parameters-as-you-need }

/// tip

```
INFO: Sending request http://www.publicobject.com/helloworld.txt on Connection{www.publicobject.com:80, proxy=DIRECT hostAddress=54.187.32.157 cipherSuite=none protocol=http/1.1}
User-Agent: OkHttp Example
Host: www.publicobject.com
Connection: Keep-Alive
Accept-Encoding: gzip

INFO: Received response for http://www.publicobject.com/helloworld.txt in 115.6ms

👯‍♂️ 💼 👉 ⛓ 👈 `item` 💪 `int` ⚖️ `str`.

#### 🎲 `None`

👆 💪 📣 👈 💲 💪 ✔️ 🆎, 💖 `str`, ✋️ 👈 ⚫️ 💪 `None`.

🐍 3️⃣.6️⃣ & 🔛 (✅ 🐍 3️⃣.1️⃣0️⃣) 👆 💪 📣 ⚫️ 🏭 & ⚙️ `Optional` ⚪️➡️ `typing` 🕹.

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

⚙️ `Optional[str]` ↩️ `str` 🔜 ➡️ 👨‍🎨 ℹ 👆 🔍 ❌ 🌐❔ 👆 💪 🤔 👈 💲 🕧 `str`, 🕐❔ ⚫️ 💪 🤙 `None` 💁‍♂️.

    }

    @Override
    public void tearDown() throws Exception {
        currentSsoType = Constants.NONE;
        super.tearDown();
    }

    // Test available() method
    public void test_available_withNoneSsoType() {
        currentSsoType = Constants.NONE;
        assertFalse(ssoManager.available());
    }

    public void test_available_withValidSsoType() {

Het tweede argument van <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is de standaardwaarde die wordt geretourneerd.

Als je dit niet meegeeft, is de standaardwaarde `None`. In dit geval gebruiken we standaard `"World"`.

///

Dan zou je dat Python-programma kunnen aanroepen:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

   */
  @get:JvmName("proxy") val proxy: Proxy?,
  protocols: List<Protocol>,
  connectionSpecs: List<ConnectionSpec>,
  /**
   * Returns this address's proxy selector. Only used if the proxy is null. If none of this
   * selector's proxies are reachable, a direct connection will be attempted.
   */
  @get:JvmName("proxySelector") val proxySelector: ProxySelector,
) {
  /**

    font-size: 10pt;
    color: #000000;
    text-decoration: none
}
a.plain {
    display: inline;
    float: none;
    width: auto;
    height: auto
}
a.sort {
    display: block;
    float: left;
    width: 100px;
    height: 15px;
    font-family: Verdana, sans-serif;
    font-size: 8pt;
    font-weight: bold;
    text-decoration: none;
    color: #000000;
    background-color: #d0d0d0;

    }

    @Override
    public CharMatcher negate() {
      return none();
    }
  }

  /** Implementation of {@link #none()}. */
  private static final class None extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new None();

    private None() {
      super("CharMatcher.none()");
    }

    @Override
    public boolean matches(char c) {

## 선택적 매개변수

같은 방법으로 기본값을 `None`으로 설정하여 선택적 매개변수를 선언할 수 있습니다:

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

이 경우 함수 매개변수 `q`는 선택적이며 기본값으로 `None` 값이 됩니다.

/// check | 확인

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | 참고

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.

 *
 * If a path's last segment is the empty string then the path ends with "/". This class always
 * builds non-empty paths: if the path is omitted it defaults to "/". The default path's segment
 * list is a single empty string: `[""]`.
 *
 * ### Query
 *
 * The query is optional: it can be null, empty, or non-empty. For many HTTP URLs the query string