code: def system(self) -> 'EFBChat':
          
          self.chat_name = "System"
          self.chat_alias = None
          self.chat_uid = EFBChat.SYSTEM_ID
          self.chat_type = ChatType.System
          return self
docs: Set the chat as a system chat.
          Only set for channel-level and group-level system chats.
  
          Returns:
              EFBChat: This object.