How to use the bs4.dammit.EntitySubstitution.substitute_xml function in bs4

def substitute(self, *args, **kwargs):
        return EntitySubstitution.substitute_xml(*args, **kwargs)

    @classmethod
    def substitute_xml(cls, ns):
        return cls._substitute_if_appropriate(
            ns, EntitySubstitution.substitute_xml)

    @classmethod
    def substitute_xml(cls, ns):
        return cls._substitute_if_appropriate(
            ns, EntitySubstitution.substitute_xml)

def substitute_xml(cls, ns):
        return cls._substitute_if_appropriate(
            ns, EntitySubstitution.substitute_xml)

"""A generic Formatter for XML."""
    REGISTRY = {}
    def __init__(self, *args, **kwargs):
        return super(XMLFormatter, self).__init__(self.XML, *args, **kwargs)


# Set up aliases for the default formatters.
HTMLFormatter.REGISTRY['html'] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html
)
HTMLFormatter.REGISTRY["html5"] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html,
    void_element_close_prefix = None
)
HTMLFormatter.REGISTRY["minimal"] = HTMLFormatter(
    entity_substitution=EntitySubstitution.substitute_xml
)
HTMLFormatter.REGISTRY[None] = HTMLFormatter(
    entity_substitution=None
)
XMLFormatter.REGISTRY["html"] =  XMLFormatter(
    entity_substitution=EntitySubstitution.substitute_html
)
XMLFormatter.REGISTRY["minimal"] = XMLFormatter(
    entity_substitution=EntitySubstitution.substitute_xml
)
XMLFormatter.REGISTRY[None] = Formatter(
    Formatter(Formatter.XML, entity_substitution=None)
)

#  needs to undergo entity substitution.
    #

    # In an HTML document, the default "html" and "minimal" functions
    # will leave the contents of 

    @classmethod
    def substitute_xml(cls, ns):
        return cls._substitute_if_appropriate(
            ns, EntitySubstitution.substitute_xml)

if self.attrs:
            for key, val in sorted(self.attrs.items()):
                if val is None:
                    decoded = key
                else:
                    if isinstance(val, list) or isinstance(val, tuple):
                        val = ' '.join(val)
                    elif not isinstance(val, basestring):
                        val = str(val)
                    if (self.contains_substitutions
                        and eventual_encoding is not None
                        and '%SOUP-ENCODING%' in val):
                        val = self.substitute_encoding(val, eventual_encoding)

                    decoded = (str(key) + '='
                               + EntitySubstitution.substitute_xml(val, True))
                attrs.append(decoded)
        close = ''
        closeTag = ''
        if self.is_empty_element:
            close = '/'
        else:
            closeTag = '' % self.name

        prefix = ''
        if self.prefix:
            prefix = self.prefix + ":"

        pretty_print = (indent_level is not None)
        if pretty_print:
            space = (' ' * (indent_level - 1))
            indent_contents = indent_level + 1