docs: def _prettify_response(self, response):
          """
          Prettify the HTML response.
  
          :param response: A Flask Response object.
          """
          if response.content_type == 'text/html; charset=utf-8':
              ugly = response.get_data(as_text=True)
              soup = BeautifulSoup(ugly, 'html.parser')
              pretty = soup.prettify(formatter='html')
              response.direct_passthrough = False
              response.set_data(pretty)
  
          return response