er          if type(request_no_context_takeover) != bool:             raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover))          self.request_no_context_takeover = request_no_context_takeover      def get_extension_string(self):         """         Returns the WebSocket extension configuration string as sent to the server.          :returns: PMCE configuration string.         :rtype: str         """         pmce_string = self.EXTENSION_NAME         if self.