code: def convert(self, request, response, data):
          
  
          if self.modifier.param in (None, 'canonical', 'local'):
              return str(request.environ['SERVER_PORT'])
          elif self.modifier.param == 'remote':
              return str(request.environ.get('REMOTE_PORT', '-'))
  
          return "-"
docs: Performs the desired Conversion.
  
          :param request: The webob Request object describing the
                          request.
          :param response: The webob Response object describing the
                           response.
          :param data: The data dictionary returned by the prepare()
                       method.
  
          :returns: A string, the results of which are the desired
                    conversion.