*   <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);

      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]")) {

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.

func (input *InputSerialization) IsEmpty() bool {
	return !input.unmarshaled
}

// UnmarshalXML - decodes XML data.
func (input *InputSerialization) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	// Make subtype to avoid recursive UnmarshalXML().
	type subInputSerialization InputSerialization
	parsedInput := subInputSerialization{}
	if err := d.DecodeElement(&parsedInput, &start); err != nil {
		return errMalformedXML(err)
	}

	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer a.CloseRespFn(resp.Body)

	return nil
}

// UnmarshalJSON - decodes JSON data.
func (a *Args) UnmarshalJSON(data []byte) error {
	// subtype to avoid recursive call to UnmarshalJSON()
	type subArgs Args
	var so subArgs

	if err := json.Unmarshal(data, &so); err != nil {
		return err
	}

	oa := Args(so)
	if oa.URL == nil || oa.URL.String() == "" {

 *
 * <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);

 *   <li>graphs that do/don't allow self-loops
 *   <li>graphs whose nodes/edges are insertion-ordered, sorted, or unordered
 *   <li>graphs whose edges have associated values
 * </ul>
 *
 * <p>{@code ValueGraph}, as a subtype of {@code Graph}, explicitly does not support parallel edges,
 * and forbids implementations or extensions with parallel edges. If you need parallel edges, use

	maximumRetentionDays  = 36500
	maximumRetentionYears = 100
)

// UnmarshalXML - decodes XML data.
func (dr *DefaultRetention) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	// Make subtype to avoid recursive UnmarshalXML().
	type defaultRetention DefaultRetention
	retention := defaultRetention{}

	if err := d.DecodeElement(&retention, &start); err != nil {
		return err
	}

        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);

    }

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

    companion object