<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def render_files(self, root=None):
 """ Render the file path as accordions """

        if root is None:
            tmp =  os.environ.get('TMP')
            root = sys.path[1 if tmp and tmp in sys.path else 0]
        items = []
        for filename in os.listdir(root):
            # for subdirname in dirnames:
            #     path = os.path.join(dirname, subdirname)
            #     items.append(FOLDER_TMPL.format(
            #         name=subdirname,
            #         id=path,
            #         items=self.render_files(path)
            #     ))
            #for filename in filenames:
            f,ext = os.path.splitext(filename)
            if ext in ['.py', '.enaml']:
                items.append(FILE_TMPL.format(
                    name=filename,
                    id=filename
                ))

        return "".join(items)