Hash {
      @Override
      Map<Element, Element> create(Collection<Element> keys) {
        Map<Element, Element> map = new HashMap<>();
        for (Element element : keys) {
          map.put(element, element);
        }
        return map;
      }
    },
    LinkedHM {
      @Override
      Map<Element, Element> create(Collection<Element> keys) {
        Map<Element, Element> map = new LinkedHashMap<>();

    }

    /**
     * Removes an element from its parent.
     *
     * @param element the element to remove
     *
     */
    public static void removeElement(Element element) {
        Editor editor = new Editor(element.document());
        editor.removeElement(element);
    }

    /**
     * Convenience method to add GAV (groupId, artifactId, version) elements to a parent.
     *

    StackTraceElement[] elements = e.getStackTrace();
    for (int i = 0; i < elements.length; i++) {
      StackTraceElement element = elements[i];
      if (element.getClassName().equals(clazz) && element.getMethodName().equals(method)) {
        return i;
      }
    }
    throw new AssertionError(
        "Expected element " + clazz + "." + method + " not found in stack trace", e);
  }

    }

    protected Element findChild(Element element, String childName) {
        NodeList childNodes = element.getChildNodes();
        for (int i = 0; i < childNodes.getLength(); i++) {
            Node node = childNodes.item(i);
            if (node instanceof Element) {
                Element childElement = (Element) node;

		name  string
		elems []string
		elem  string
		out   bool
	}{
		{"exists", []string{"1", "2", "3"}, "1", true},
		{"not exists", []string{"1", "2", "3"}, "4", false},
	}
	for _, test := range containsTests {
		t.Run(test.name, func(t *testing.T) {
			if out := Contains(test.elems, test.elem); test.out != out {
				t.Errorf("Contains(%v, %s) want: %t, got: %t", test.elems, test.elem, test.out, out)
			}
		})

    /**
     * Returns the number of occurrences of {@code element} in this multiset.
     *
     * @param element the element to look for
     * @return the nonnegative number of occurrences of the element
     */
    @Override
    public int count(@Nullable Object element) {
      try {
        return unbox(countMap.get(element));
      } catch (NullPointerException | ClassCastException e) {
        return 0;

        for (Element element : classDoc.getComment()) {
            parent.appendChild(document.importNode(element, true));
        }
        NodeList otherContent = classDoc.getClassSection().getChildNodes();
        for (int i = 0; i < otherContent.getLength(); i++) {
            Node child = otherContent.item(i);
            if (child instanceof Element && !((Element) child).getTagName().equals("section")) {

                for (PluginExecution element : tgt) {
                    Object key = getPluginExecutionKey(element);
                    merged.put(key, element);
                }

                for (PluginExecution element : src) {
                    Object key = getPluginExecutionKey(element);
                    PluginExecution existing = merged.get(key);

    final int hash;

    Element(int hash) {
      this.hash = hash;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      return this == obj || (obj instanceof Element && ((Element) obj).hash == hash);
    }

    @Override
    public int hashCode() {
      return hash;
    }

    @Override
    public int compareTo(Element that) {

        }
        Element element = document.createElement("classname");
        element.appendChild(document.createTextNode(className));
        return element;
    }

    public Node link(MethodMetaData method, GenerationListener listener) {
        if (model.isKnownType(method.getOwnerClass().getClassName())) {
            Element apilink = document.createElement("apilink");