#我以为是要分开出现错误所以分步了……

class Student(object):
    def __init__(self, name, score):
        self.name = name
        self.score = score
    def get_grade(self):
        if self.score < 0:
            raise ValueError
        elif self.score > 100:
            raise ValueError
        else:
            if self.score >= 80:
                return 'A'        
            if self.score >= 60:
                return 'B'
            return 'C'