class Person:
  def setname(self, name):
    if len(name) < 3:
      raise ValueError('名称长度必须大于3！')
    self.__name = name
    
  def getname(self):
    return self.__name
  
  #为name配置setter和getter方法
  name = property(getname, setname)
  
  def setage(self, age):
    if age < 100:
      self.__age = age
    else:
      raise ValueError('年龄必须小于100！')
  
  def getage(self):
    return self.__age
  
  #为age配置getter和setter方法
  age = property(getage, setage)
  
  #定义私有方法
  def __display(self):
    print(self.__name, "今年", self.__age, "岁。")
    
xiaobai = Person()
xiaobai.name = "xiaobai"
xiaobai.age = 20
#直接调用隐藏的display()方法
xiaobai._Person__display()