code: def fromSuccessResponse(cls, success_response):
          
          self = cls()
  
          # PAPE requires that the args be signed.
          args = success_response.getSignedNS(self.ns_uri)
  
          # Only try to construct a PAPE response if the arguments were
          # signed in the OpenID response.  If not, return None.
          if args is not None:
              self.parseExtensionArgs(args)
              return self
          else:
              return None
docs: Create a C{L{Response}} object from a successful OpenID
          library response
          (C{L{openid.consumer.consumer.SuccessResponse}}) response
          message
  
          @param success_response: A SuccessResponse from consumer.complete()
          @type success_response: C{L{openid.consumer.consumer.SuccessResponse}}
  
          @rtype: Response or None
          @returns: A provider authentication policy response from the
              data that was supplied with the C{id_res} response or None
              if the provider sent no signed PAPE response arguments.