class Student(object):

@property
def score(self):
    return self._score

@score.setter
def score(self, value):
    if not isinstance(value, int):
        raise ValueError('score must be an integer!')
    if value < 0 or value > 100:
        raise ValueError('score must between 0 ~ 100!')
    self._score = value

请问大家这里面的 self._score用下划线和self.score作区分的意义在哪里，想不明白