old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  
  class Programer(object):
      hobby = 'Play Computer'
  
      def __init__(self, name, age, weight):
          self.name = name
          self._age = age
          self.__weight = weight
  
  
  if __name__ == '__main__':
      programer = Programer('Albert', 25, 80)
      print dir(programer)
      print programer.__dict__
  
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  
  class Programer(object):
      hobby = 'Play Computer'
  
      def __init__(self, name, age, weight):
          self.name = name
          self._age = age
          self.__weight = weight
  
      def get_weight(self):
          return self.__weight
  
  
  if __name__ == '__main__':
      programer = Programer('Albert', 25, 80)
      print dir(programer)
      print programer.__dict__
      print programer.get_weight()
      print programer._Programer__weight
  
  
subject: update sample code