*       Serializable}.
   *   <li>Serialization test is not performed on method return values unless the method is a
   *       visible static factory method whose return type is {@code C} or {@code C}'s subtype.
   * </ul>
   *
   * <p>In all cases, if {@code C} needs custom logic for testing serialization, you can add an
   * explicit {@code testSerializable()} test in the corresponding {@code CTest} class, and {@code

   *   <li>Nulls test is not performed on method return values unless the method is a non-private
   *       static factory method whose return type is {@code cls} or {@code cls}'s subtype.
   * </ul>
   */
  public void testNulls(Class<?> cls) {
    try {
      doTestNulls(cls, Visibility.PACKAGE);
    } catch (Exception e) {
      throwIfUnchecked(e);
      throw new RuntimeException(e);

    val keyPair: KeyPair = heldCertificate.keyPair()
  }

  @Test @Disabled
  fun mediaType() {
    val mediaType: MediaType = MediaType.get("")
    val type: String = mediaType.type()
    val subtype: String = mediaType.subtype()
    val parse: MediaType? = MediaType.parse("")
  }

  @Test @Disabled
  fun mockResponse() {
    val mockResponse = MockResponse()
    var status: String = mockResponse.getStatus()

      }
    }

  companion object {
    /**
     * The "mixed" subtype of "multipart" is intended for use when the body parts are independent
     * and need to be bundled in a particular order. Any "multipart" subtypes that an implementation
     * does not recognize must be treated as being of subtype "mixed".
     */
    @JvmField
    val MIXED = "multipart/mixed".toMediaType()

    /**

      if (responseCode != 200 || contentType == null) {
        return;
      }

      MediaType mediaType = MediaType.parse(contentType);
      if (mediaType == null || !mediaType.subtype().equalsIgnoreCase("html")) {
        return;
      }

      Document document = Jsoup.parse(response.body().string(), url.toString());
      for (Element element : document.select("a[href]")) {

        String result = StringUtil.join(",", "z", "y", "x", "w", "v");
        assertEquals("z,y,x,w,v", result);
    }

    @Test
    @DisplayName("Should handle delimiter as CharSequence subtype")
    void testJoinWithCharSequenceDelimiter() {
        StringBuilder delimiter = new StringBuilder(" | ");
        String result = StringUtil.join(delimiter, "one", "two");
        assertEquals("one | two", result);

With **FastAPI**, you can define, validate, document, and use arbitrarily deeply nested models (thanks to Pydantic).

## List fields { #list-fields }

You can define an attribute to be a subtype. For example, a Python `list`:

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

This will make `tags` be a list, although it doesn't declare the type of the elements of the list.

 *
 * <p>In addition to convenience methods, {@link TypeToken#method} and {@link TypeToken#constructor}
 * will resolve the type parameters of the method or constructor in the context of the owner type,
 * which may be a subtype of the declaring class. For example:
 *
 * {@snippet :
 * Method getMethod = List.class.getMethod("get", int.class);
 * Invokable<List<String>, ?> invokable = new TypeToken<List<String>>() {}.method(getMethod);

   * @throws NullPointerException if any of {@code elements} is null
   */
  public static <E> ImmutableSortedSet<E> copyOf(Iterable<? extends E> elements) {
    // Hack around E not being a subtype of Comparable.
    // Unsafe, see ImmutableSortedSetFauxverideShim.
    @SuppressWarnings("unchecked")
    Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable<?>>natural();
    return copyOf(naturalOrder, elements);

    }

    private fun bodyIsStreaming(response: Response): Boolean {
      val contentType = response.body.contentType()
      return contentType != null && contentType.type == "text" && contentType.subtype == "event-stream"
    }

    companion object