How to use the html5lib.treebuilders.base function in html5lib

if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):
        return list(self.attrs.items())
    def keys(self):
        return list(self.attrs.keys())
    def __len__(self):
        return len(self.attrs)
    def __getitem__(self, name):
        return self.attrs[name]
    def __contains__(self, name):
        return name in list(self.attrs.keys())


class Element(treebuilder_base.Node):
    def __init__(self, element, soup, namespace):
        treebuilder_base.Node.__init__(self, element.name)
        self.element = element
        self.soup = soup
        self.namespace = namespace

    def appendChild(self, node):
        string_child = child = None
        if isinstance(node, str):
            # Some other piece of code decided to pass in a string
            # instead of creating a TextElement object to contain the
            # string.
            string_child = child = node
        elif isinstance(node, Tag):
            # Some other piece of code decided to pass in a Tag
            # instead of creating an Element object to contain the

if not isinstance(value, list):
                value = whitespace_re.split(value)
        self.element[name] = value
    def items(self):
        return list(self.attrs.items())
    def keys(self):
        return list(self.attrs.keys())
    def __len__(self):
        return len(self.attrs)
    def __getitem__(self, name):
        return self.attrs[name]
    def __contains__(self, name):
        return name in list(self.attrs.keys())


class Element(treebuilder_base.Node):
    def __init__(self, element, soup, namespace):
        treebuilder_base.Node.__init__(self, element.name)
        self.element = element
        self.soup = soup
        self.namespace = namespace

    def appendChild(self, node):
        string_child = child = None
        if isinstance(node, basestring):
            # Some other piece of code decided to pass in a string
            # instead of creating a TextElement object to contain the
            # string.
            string_child = child = node
        elif isinstance(node, Tag):
            # Some other piece of code decided to pass in a Tag
            # instead of creating an Element object to contain the

rv.append(element.text)

            for child in element:
                serializeElement(child)

            rv.append("" % (element.tag,))

        if hasattr(element, "tail") and element.tail:
            rv.append(element.tail)

    serializeElement(element)

    return "".join(rv)


class TreeBuilder(base.TreeBuilder):
    documentClass = Document
    doctypeClass = DocumentType
    elementClass = None
    commentClass = None
    fragmentClass = Document
    implementation = etree

    def __init__(self, namespaceHTMLElements, fullTree=False):
        builder = etree_builders.getETreeModule(etree, fullTree=fullTree)
        infosetFilter = self.infosetFilter = _ihatexml.InfosetFilter(preventDoubleDashComments=True)
        self.namespaceHTMLElements = namespaceHTMLElements

        class Attributes(dict):
            def __init__(self, element, value=None):
                if value is None:
                    value = {}

def getFragment(self):
        return treebuildersbase.TreeBuilder.getFragment(self).element

def cloneNode(self):
            return NodeBuilder(self.element.cloneNode(False))

        def hasContent(self):
            return self.element.hasChildNodes()

        def getNameTuple(self):
            if self.namespace is None:
                return namespaces["html"], self.name
            else:
                return self.namespace, self.name

        nameTuple = property(getNameTuple)

    class TreeBuilder(base.TreeBuilder):  # pylint:disable=unused-variable
        def documentClass(self):
            self.dom = Dom.getDOMImplementation().createDocument(None, None, None)
            return weakref.proxy(self)

        def insertDoctype(self, token):
            name = token["name"]
            publicId = token["publicId"]
            systemId = token["systemId"]

            domimpl = Dom.getDOMImplementation()
            doctype = domimpl.createDocumentType(name, publicId, systemId)
            self.document.appendChild(NodeBuilder(doctype))
            if Dom == minidom:
                doctype.ownerDocument = self.dom

        def elementClass(self, name, namespace=None):

if not isinstance(value, list):
                value = nonwhitespace_re.findall(value)
        self.element[name] = value
    def items(self):
        return list(self.attrs.items())
    def keys(self):
        return list(self.attrs.keys())
    def __len__(self):
        return len(self.attrs)
    def __getitem__(self, name):
        return self.attrs[name]
    def __contains__(self, name):
        return name in list(self.attrs.keys())


class Element(treebuilder_base.Node):
    def __init__(self, element, soup, namespace):
        treebuilder_base.Node.__init__(self, element.name)
        self.element = element
        self.soup = soup
        self.namespace = namespace

    def appendChild(self, node):
        string_child = child = None
        if isinstance(node, str):
            # Some other piece of code decided to pass in a string
            # instead of creating a TextElement object to contain the
            # string.
            string_child = child = node
        elif isinstance(node, Tag):
            # Some other piece of code decided to pass in a Tag
            # instead of creating an Element object to contain the

def getFragment(self):
        return treebuildersbase.TreeBuilder.getFragment(self).element

def __init__(self, element):
            base.Node.__init__(self, element.nodeName)
            self.element = element

# Encoding object. We want to use a string for compatibility
                # with other tree builders.
                original_encoding = original_encoding.name
            doc.original_encoding = original_encoding

    def create_treebuilder(self, namespaceHTMLElements):
        self.underlying_builder = TreeBuilderForHtml5lib(
            namespaceHTMLElements, self.soup)
        return self.underlying_builder

    def test_fragment_to_document(self, fragment):
        """See `TreeBuilder`."""
        return u'%s' % fragment


class TreeBuilderForHtml5lib(treebuilder_base.TreeBuilder):

    def __init__(self, namespaceHTMLElements, soup=None):
        if soup:
            self.soup = soup
        else:
            from bs4 import BeautifulSoup
            self.soup = BeautifulSoup("", "html.parser")
        super(TreeBuilderForHtml5lib, self).__init__(namespaceHTMLElements)

    def documentClass(self):
        self.soup.reset()
        return Element(self.soup, self.soup, None)

    def insertDoctype(self, token):
        name = token["name"]
        publicId = token["publicId"]

def __init__(self, element, soup, namespace):
        treebuildersbase.Node.__init__(self, element.name)
        self.element = element
        self.soup = soup
        self.namespace = namespace