How to use the fair.utility.rst_to_html function in fair

def __parse_doc_field(self, app, method, doc_field):
        name = doc_field.children[0].astext()
        content = rst_to_html(doc_field.children[1].rawsource)
        if name == 'response':
            self.response = app.config['responses'][content]
        elif name == 'plugin':
            for item in content.split():
                plugin = app.config['plugins'].get(item)
                if not plugin:
                    raise Exception('%s use undefined plugin %s' % (method.__name__, item))
                self.plugins.append(plugin)
                self.plugin_keys.append(item)
                for error_code, error_message in plugin.error_codes.items():
                    self.__meta_code_set(error_code, error_message, 'plugin ' + item)
        elif name.startswith('raise '):
            self.__meta_code_set(name[6:], content)
        elif name.startswith('param '):
            items = name[6:].split()
            param_type = items[0]

def doc_ui():
    views = app.api.url_map[request.url_rule.rule[:-5]]
    apis = []
    for view_func in views:
        meta = view_func.meta       # type: Meta
        response_doc = rst_to_html(meta.response_cls.__doc__)
        apis.append(ContextClass(title=text_to_html(meta.title), description=text_to_html(meta.description),
                                 methods=meta.http_methods, meta=meta, response_doc=response_doc))
    return render_template('doc.html', apis=apis)    # url 为 flask 模板内置变量

def __parse_doc_tree(self, view_func, doc_tree):
        if type(doc_tree) == docutils.nodes.term:
            self.title = rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.paragraph:
            if self.description is None:
                self.title = self.title + rst_to_html(doc_tree.rawsource)
                self.description = ''
            elif self.description == '':
                self.description = rst_to_html(doc_tree.rawsource)
            else:
                self.description = self.description + os.linesep * 2 + rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.field:
            self.__parse_doc_field(view_func, doc_tree)
            return

        for item in doc_tree.children:
            self.__parse_doc_tree(view_func, item)

def __parse_doc_tree(self, view_func, doc_tree):
        if type(doc_tree) == docutils.nodes.term:
            self.title = rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.paragraph:
            if self.description is None:
                self.title = self.title + rst_to_html(doc_tree.rawsource)
                self.description = ''
            elif self.description == '':
                self.description = rst_to_html(doc_tree.rawsource)
            else:
                self.description = self.description + os.linesep * 2 + rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.field:
            self.__parse_doc_field(view_func, doc_tree)
            return

def __parse_doc_tree(self, view_func, doc_tree):
        if type(doc_tree) == docutils.nodes.term:
            self.title = rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.paragraph:
            if self.description is None:
                self.title = self.title + rst_to_html(doc_tree.rawsource)
                self.description = ''
            elif self.description == '':
                self.description = rst_to_html(doc_tree.rawsource)
            else:
                self.description = self.description + os.linesep * 2 + rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.field:
            self.__parse_doc_field(view_func, doc_tree)
            return

        for item in doc_tree.children:
            self.__parse_doc_tree(view_func, item)

def __parse_doc_tree(self, app, method, doc_tree):
        if type(doc_tree) == docutils.nodes.term:
            self.title = rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.paragraph:
            if self.description is None:
                self.title = self.title + rst_to_html(doc_tree.rawsource)
                self.description = ''
            elif self.description == '':
                self.description = rst_to_html(doc_tree.rawsource)
            else:
                self.description = self.description + os.linesep * 2 + rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.field:
            self.__parse_doc_field(app, method, doc_tree)
            return

def __parse_doc_tree(self, view_func, doc_tree):
        if type(doc_tree) == docutils.nodes.term:
            self.title = rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.paragraph:
            if self.description is None:
                self.title = self.title + rst_to_html(doc_tree.rawsource)
                self.description = ''
            elif self.description == '':
                self.description = rst_to_html(doc_tree.rawsource)
            else:
                self.description = self.description + os.linesep * 2 + rst_to_html(doc_tree.rawsource)
            return

        if type(doc_tree) == docutils.nodes.field:
            self.__parse_doc_field(view_func, doc_tree)
            return

        for item in doc_tree.children:
            self.__parse_doc_tree(view_func, item)

def __response(self, *args, **kwargs):
        try:
            # get request parameters
            self.params = get_request_params(request)
            self.params_proto = self.params.copy()

            if self.params.get('__fair') == 'doc':
                response_doc = None
                if self.method.meta.response:
                    response_doc = rst_to_html(self.method.meta.response.__doc__)
                return render_template('doc.html',
                                       title='DOC UI',
                                       api_uri=self.uri,
                                       method=request.method,
                                       meta=self.method.meta,
                                       api_title=text_to_html(self.method.meta.title),
                                       response_doc=response_doc,
                                       description=text_to_html(self.method.meta.description))

            # plugin
            for plugin in self.meta.plugins:
                plugin.before_request(self)
                for parameter in plugin.parameters:
                    del self.params[parameter[0]]

            # structure parameters