assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(4, 6)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 4)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 3)));
  }

  public void testGap_invalidRangesWithInfinity() {
    assertThrows(IllegalArgumentException.class, () -> Range.atLeast(1).gap(Range.atLeast(2)));

   *
   * <p>For example, the gap of {@code [1..5]} and {@code (7..10)} is {@code (5..7]}. The resulting
   * range may be empty; for example, the gap between {@code [1..5)} {@code [5..7)} yields the empty
   * range {@code [5..5)}.
   *
   * <p>The gap exists if and only if the two ranges are either disconnected or immediately adjacent

   */
  private static String hextetsToIPv6String(int[] hextets) {
    // While scanning the array, handle these state transitions:
    //   start->num => "num"     start->gap => "::"
    //   num->num   => ":num"    num->gap   => "::"
    //   gap->num   => "num"     gap->gap   => ""
    StringBuilder buf = new StringBuilder(39);
    boolean lastWasNumber = false;
    for (int i = 0; i < hextets.length; i++) {

   *
   * <p>For example, the gap of {@code [1..5]} and {@code (7..10)} is {@code (5..7]}. The resulting
   * range may be empty; for example, the gap between {@code [1..5)} {@code [5..7)} yields the empty
   * range {@code [5..5)}.
   *
   * <p>The gap exists if and only if the two ranges are either disconnected or immediately adjacent

      env:
        # Set the DEVELOCITY_ACCESS_KEY so that Gradle Build Scans are generated
        DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
        # Potential stop-gap solution for ReadTimeout issues with the Gradle Build Cache
        # https://gradle.slack.com/archives/CHDLT99C6/p1636477584059200
        GRADLE_OPTS: -Dhttp.keepAlive=false

    - name: Compile with Gradle without Build Scan

   */
  private static String hextetsToIPv6String(int[] hextets) {
    // While scanning the array, handle these state transitions:
    //   start->num => "num"     start->gap => "::"
    //   num->num   => ":num"    num->gap   => "::"
    //   gap->num   => "num"     gap->gap   => ""
    StringBuilder buf = new StringBuilder(39);
    boolean lastWasNumber = false;
    for (int i = 0; i < hextets.length; i++) {

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

Sử dụng `Optional[str]` thay cho `str` sẽ cho phép trình soạn thảo giúp bạn phát hiện các lỗi mà bạn có thể gặp như một giá trị luôn là một `str`, trong khi thực tế nó rất có thể là `None`.

`Optional[Something]` là một cách viết ngắn gọn của `Union[Something, None]`, chúng là tương đương nhau.

oup>.card:not(:first-child) .card-img-bottom{border-bottom-left-radius:0}}.card-columns .card{margin-bottom:.75rem}@media (min-width:576px){.card-columns{-webkit-column-count:3;-moz-column-count:3;column-count:3;-webkit-column-gap:1.25rem;-moz-column-gap:1.25rem;column-gap:1.25rem;orphans:1;widows:1}.card-columns .card{display:inline-block;width:100%}}.accordion{overflow-anchor:none}.accordion>.card{overflow:hidden}.accordion>.card:not(:last-of-type){border-bottom:0;border-bottom-right-radius:0;...

modifier. Can be `scrollParent`, `window`,\n     * `viewport` or any DOM element.\n     */\n    boundariesElement: 'scrollParent',\n  },\n\n  /**\n   * Modifier used to make sure the reference and its popper stay near each other\n   * without leaving any gap between the two. Especially useful when the arrow is\n   * enabled and you want to ensure that it points to its reference element.\n   * It cares only about the first axis. You can still have poppers with margin\n   * between the popper and its reference...

ius: 0;\n  }\n}\n\n.card-columns .card {\n  margin-bottom: 0.75rem;\n}\n\n@media (min-width: 576px) {\n  .card-columns {\n    -webkit-column-count: 3;\n    -moz-column-count: 3;\n    column-count: 3;\n    -webkit-column-gap: 1.25rem;\n    -moz-column-gap: 1.25rem;\n    column-gap: 1.25rem;\n    orphans: 1;\n    widows: 1;\n  }\n  .card-columns .card {\n    display: inline-block;\n    width: 100%;\n  }\n}\n\n.accordion {\n  overflow-anchor: none;\n}\n\n.accordion > .card {\n  overflow: hidden;\n}\n\n.accordion...