code: def _docf(self, tag, val):
          
          if tag == 'type':
              return ':class:`{}`'.format(val)
          elif tag == 'route':
              if self.args.route_method:
                  return ':meth:`%s`' % self.args.route_method.format(
                      ns=self.cur_namespace.name, route=fmt_func(val))
              else:
                  return val
          elif tag == 'link':
              anchor, link = val.rsplit(' ', 1)
              return '`{} <{}>`_'.format(anchor, link)
          elif tag == 'val':
              if val == 'null':
                  return 'None'
              elif val == 'true' or val == 'false':
                  return '``{}``'.format(val.capitalize())
              else:
                  return val
          elif tag == 'field':
              return '``{}``'.format(val)
          else:
              raise RuntimeError('Unknown doc ref tag %r' % tag)
docs: Callback used as the handler argument to process_docs(). This converts
          Stone doc references to Sphinx-friendly annotations.