text: class Student1(object):
  
      def __init__(self):
          self._score = None
  
      def set_score(self, score):
          if not isinstance(score, int):
              raise ValueError('score must be an integer!')
          if score < 0 or score > 100:
              raise ValueError('score must between 0 ~ 100!')
          self._score = score
  
      def get_score(self):
          return self._score
  
  s1 = Student1()
  # s1.set_score('1')
  # s1.set_score(200)
  s1.set_score(99)
  print(s1.get_score())
  
  
  class Student2(object):
  
      def __init__(self):
          self._score = None
  
      @property
      def score(self):
          return self._score
  
      @score.setter
      def score(self, score):
          if not isinstance(score, int):
              raise ValueError('score must be an integer!')
          if score < 0 or score > 100:
              raise ValueError('score must between 0 ~ 100!')
          self._score = score
  
  s2 = Student2()
  # s2.score = 'a'
  # s2.score = 101
  s2.score = 100
  print(s2.score)
  