code: def header(self, text, level, raw=None):
          
          return '\n{0}\n{1}\n'.format(text, self.hmarks[level] * len(text))
docs: Rendering header/heading tags like ``<h1>`` ``<h2>``.
  
          :param text: rendered text content for the header.
          :param level: a number for the header level, for example: 1.
          :param raw: raw text content of the header.