old_contents: class WebQQClient(object):
  
      def login(self, username=None, password=None):
          return True
  
      def logout(self):
          return True
  
      def run_forever(self):
          i=0
          while True:
              i=i+1
              if i>100:
                  break
              print i
  
new_contents: class WebQQClient(object):
  
      def login(self, username=None, password=None):
          return True
  
      def logout(self):
          return True
  
      def heartbeat(self):
          print 'Bom..bong!'
  
      def run_forever(self):
          i=0
          while True:
              i=i+1
              if i>100:
                  break
              print i
  
subject: 添加 heartbeat 心跳函数