for (V element : elements) {
      assertFalse("Should not contain value " + element, getMap().containsValue(element));
    }
  }

  /** @return an array of the proper size with {@code null} as the key of the middle element. */
  protected Entry<K, V>[] createArrayWithNullKey() {
    Entry<K, V>[] array = createSamplesArray();
    int nullKeyLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullKeyLocation];

[data-ty] {
    display: block;
    line-height: 2;
}

[data-ty]:before {
    /* Set up defaults and ensure empty lines are displayed. */
    content: '';
    display: inline-block;
    vertical-align: middle;
}

[data-ty="input"]:before,
[data-ty-prompt]:before {
    margin-right: 0.75em;
    color: var(--color-text-subtle);
}

[data-ty="input"]:before {
    content: '$';
}

  }

  /** @see AbstractContainerTester#resetContainer() */
  protected void resetCollection() {
    resetContainer();
  }

  /** @return an array of the proper size with {@code null} inserted into the middle element. */
  protected E[] createArrayWithNullElement() {
    E[] array = createSamplesArray();
    array[getNullLocation()] = null;
    return array;
  }

  protected void initCollectionWithNullElement() {

    assert (
        '"syntaxHighlight": false' not in response.text
    ), "not used parameters should not be included"
    assert (
        '"syntaxHighlight.theme": "obsidian"' in response.text
    ), "parameters with middle dots should be included in a JSON compatible way"
    assert (
        '"dom_id": "#swagger-ui"' in response.text
    ), "default configs should be preserved"

<img src="/img/tutorial/extending-openapi/image03.png">

## Change the Theme

The same way you could set the syntax highlighting theme with the key `"syntaxHighlight.theme"` (notice that it has a dot in the middle):

```Python hl_lines="3"
{!../../../docs_src/configure_swagger_ui/tutorial002.py!}
```

That configuration would change the syntax highlighting color theme:

                .named("Floats.asList, tail subList"),
            ListTestSuiteBuilder.using(new FloatsAsListMiddleSubListGenerator())
                .named("Floats.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Float> builder : builders) {
      suite.addTest(
          builder
              .withFeatures(
                  CollectionSize.ONE,

                .named("Longs.asList, tail subList"),
            ListTestSuiteBuilder.using(new LongsAsListMiddleSubListGenerator())
                .named("Longs.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Long> builder : builders) {
      suite.addTest(
          builder
              .withFeatures(
                  CollectionSize.ONE,

                .named("Ints.asList, tail subList"),
            ListTestSuiteBuilder.using(new IntsAsListMiddleSubListGenerator())
                .named("Ints.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Integer> builder : builders) {
      suite.addTest(
          builder
              .withFeatures(

                .named("Bytes.asList, tail subList"),
            ListTestSuiteBuilder.using(new BytesAsListMiddleSubListGenerator())
                .named("Bytes.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Byte> builder : builders) {
      suite.addTest(
          builder
              .withFeatures(
                  CollectionSize.ONE,

                .named("Longs.asList, tail subList"),
            ListTestSuiteBuilder.using(new LongsAsListMiddleSubListGenerator())
                .named("Longs.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Long> builder : builders) {
      suite.addTest(
          builder
              .withFeatures(
                  CollectionSize.ONE,