黑马程序员python教程，8天python从入门到精通，学python看这套就

class phone:
   __is_5g_enable =  0
   def __check_5g__(self):
      print("正在通话中")
   def call_by_5g(self):
      if self.__is_5g_enable:
         print("5g开启")
      else:
         print("5g关闭，使用4g网络")
         self.__check_5g__()
phone = phone()
phone.call_by_5g()