* @return the algorithm name
     */
    public static String getAlgorithmName(int algorithm) {
        switch (algorithm) {
        case COMPRESSION_NONE:
            return "None";
        case COMPRESSION_LZ77:
            return "LZ77";
        case COMPRESSION_LZ77_HUFFMAN:
            return "LZ77+Huffman";
        case COMPRESSION_LZNT1:
            return "LZNT1";

        sb.append("       id: ").append(getId()).append('\n');
        sb.append("      url: ").append(getUrl()).append('\n');
        sb.append("   layout: ").append(layout != null ? layout : "none").append('\n');

        if (snapshots != null) {
            sb.append("snapshots: [enabled => ").append(snapshots.isEnabled());
            sb.append(", update => ").append(snapshots.getUpdatePolicy()).append("]\n");

     *
     * @param key the key for which to retrieve the session data, must not be {@code null}
     * @return the session data associated with the key or {@code null} if none
     */
    @Nullable
    <T> T get(@Nonnull Key<T> key);

    /**
     * Retrieve of compute the data associated with the specified key.
     *

    }

    @Test
    @DisplayName("Test algorithm names")
    public void testAlgorithmNames() {
        assertEquals("None", compressionService.getAlgorithmName(CompressionService.COMPRESSION_NONE));
        assertEquals("LZ77", compressionService.getAlgorithmName(CompressionService.COMPRESSION_LZ77));

    * `dict`의 값(value)는 `float`타입이다. (각 아이템의 가격(price))

#### `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`

    SerializableTester.reserializeAndAssert(Ints.stringConverter());
  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Integer> none = Arrays.<Integer>asList();
    assertThat(Ints.toArray(none)).isEqualTo(EMPTY);

    List<Integer> one = Arrays.asList((int) 1);
    assertThat(Ints.toArray(one)).isEqualTo(ARRAY1);

    int[] array = {(int) 0, (int) 1, (int) 0xdeadbeef};

    RealConnectionPool(
      taskRunner = taskRunner,
      maxIdleConnections = maxIdleConnections,
      keepAliveDuration = 100L,
      timeUnit = TimeUnit.NANOSECONDS,
      connectionListener = ConnectionListener.NONE,
      exchangeFinderFactory = { pool, address, user ->
        FastFallbackExchangeFinder(
          routePlanner ?: RealRoutePlanner(
            taskRunner = taskRunner,
            connectionPool = pool,

    immutable = immutable,
    headerValue = headerValue,
  )
}

/**
 * Returns the next index in this at or after [startIndex] that is a character from
 * [characters]. Returns the input length if none of the requested characters can be found.
 */
private fun String.indexOfElement(
  characters: String,
  startIndex: Int = 0,
): Int {
  for (i in startIndex until length) {
    if (this[i] in characters) {

xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='m2 5 6 6 6-6'/%3e%3c/svg%3e");display:block;width:100%;padding:.375rem 2.25rem .375rem .75rem;font-size:1rem;font-weight:400;line-height:1.5;color:var(--bs-body-color);background-color:var(--bs-body-bg);background-image:var(--bs-form-select-bg-img),var(--bs-form-select-bg-icon,none);background-repeat:no-repeat;background-position:right .75rem ...

     */
    @Nonnull
    String prefix();

    /**
     * Returns the text content of this XML node.
     *
     * @return the node's text value, or {@code null} if none exists
     */
    @Nullable
    String value();

    /**
     * Returns an immutable map of all attributes defined on this XML node.
     *