How to use the hotdoc.utils.loggable.debug function in hotdoc

def __format_symbols(self, formatter, link_resolver):
        for symbol in self.symbols:
            if symbol is None:
                continue
            debug('Formatting symbol %s in page %s' % (
                symbol.unique_name, self.name), 'formatting')
            symbol.detailed_description = formatter.format_symbol(
                symbol, link_resolver)

tsl = self.typed_symbols.get(type(symbol))
        if tsl:
            tsl.symbols.append(symbol)

            by_parent_symbols = self.by_parent_symbols.get(symbol.parent_name)
            if not by_parent_symbols:
                by_parent_symbols = self.__get_empty_typed_symbols()
                parent_name = symbol.parent_name
                if parent_name is None:
                    parent_name = 'Others symbols'
                self.by_parent_symbols[symbol.parent_name] = by_parent_symbols
            by_parent_symbols.get(type(symbol)).symbols.append(symbol)

        self.symbols.append(symbol)

        debug('Resolved symbol %s to page %s' %
              (symbol.unique_name, self.link.ref), 'resolution')

def debug(message):
    core_debug(message, domain='c-extension')

def parse_toplevel_config(self, config):
        """Parse @config to setup @self state."""
        if not Formatter.initialized:
            html_theme = config.get('html_theme', 'default')

            if html_theme != 'default':
                uri = urllib.parse.urlparse(html_theme)
                if not uri.scheme:
                    html_theme = config.get_path('html_theme')
                    debug("Using theme located at %s" % html_theme)
                elif uri.scheme.startswith('http'):
                    html_theme = self.__download_theme(uri)

            if html_theme == 'default':
                default_theme = os.path.join(HERE, os.pardir,
                                             'hotdoc_bootstrap_theme', 'dist')

                html_theme = os.path.abspath(default_theme)
                debug("Using default theme")

            theme_meta_path = os.path.join(html_theme, 'theme.json')

            if os.path.exists(theme_meta_path):
                with open(theme_meta_path, 'r') as _:
                    Formatter.theme_meta = json.loads(_.read())

def __format_symbols(self, formatter, link_resolver):
        for symbol in self.symbols:
            if symbol is None:
                continue
            debug('Formatting symbol %s in page %s' % (
                symbol.unique_name, self.source_file), 'formatting')
            symbol.skip = not formatter.format_symbol(symbol, link_resolver)

wset = pkg_resources.WorkingSet([])
    distributions, _ = wset.find_plugins(pkg_resources.Environment(paths))

    for dist in distributions:
        sys.path.append(dist.location)
        wset.add(dist)

    for entry_point in wset.iter_entry_points(group='hotdoc.extensions',
                                              name='get_extension_classes'):
        try:
            activation_function = entry_point.load()
            classes = activation_function()
        # pylint: disable=broad-except
        except Exception as exc:
            info("Failed to load %s %s" % (entry_point.module_name, exc))
            debug(traceback.format_exc())
            continue

        for klass in classes:
            extra_classes.append(klass)

    return extra_classes

def rename_symbol(self, unique_name, target):
        sym = self.__symbols.get(target)
        if sym:
            for alias in self.__aliased[unique_name]:
                alias.target = unique_name
            if sym.unique_name == sym.display_name:
                sym.display_name = unique_name
            sym.unique_name = unique_name
            del self.__symbols[target]
            self.__symbols[unique_name] = sym
            debug('Renamed symbol with unique name %s to %s' % (target, unique_name))
        return sym

tsl = self.typed_symbols.get(type(symbol))
        if tsl:
            tsl.symbols.append(symbol)

            by_parent_symbols = self.by_parent_symbols.get(symbol.parent_name)
            if not by_parent_symbols:
                by_parent_symbols = self.__get_empty_typed_symbols()
                parent_name = symbol.parent_name
                if parent_name is None:
                    parent_name = 'Others symbols'
                self.by_parent_symbols[symbol.parent_name] = by_parent_symbols
            by_parent_symbols.get(type(symbol)).symbols.append(symbol)

        self.symbols.append(symbol)

        debug('Resolved symbol %s to page %s' %
              (symbol.display_name, self.link.ref), 'resolution')