old_contents: import psutil
  import json
  
  from rpcservice.rpcservice import RPCService
  
  from decorator.serialize import serialize
  from decorator.singleton import singleton
  
  
  @singleton()
  @serialize()
  class SystemService(RPCService):
  
      def get_server_status(self):
          system_status = {
              "cpu": psutil.cpu_percent(),
              "memory": psutil.virtual_memory().percent,
          }
          json_obj = []
          json_obj.append(system_status)
          return json_obj
  
      def get_server_version(self):
          pass
  
new_contents: import psutil
  import json
  
  from rpcservice.rpcservice import RPCService
  
  from decorator.serialize import serialize
  from decorator.singleton import singleton
  
  
  @singleton()
  @serialize()
  class SystemService(RPCService):
  
      def get_server_status(self):
          system_status = {
              "cpu": psutil.cpu_percent(),
              "memory": psutil.virtual_memory().percent,
          }
          json_obj = []
          json_obj.append(system_status)
          return json_obj
  
      def get_server_version(self):
          pass
  
      def message_q(self):
          pass
  
subject: add not implement method.