class Student(object):

    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_score(self):
        print('%s: %s' % (self.name, self.score))

    def get_grade(self):
        if self.score >= 90:
            return 'A'
        elif self.score >= 60:
            return 'B'
        else:
            return 'C'

bart = Student('Bart Simpson', 59)
lisa = Student('Lisa Simpson', 87)

print('bart.name =', bart.name)
print('bart.score =', bart.score)
bart.print_score()

print('grade of Bart:', bart.get_grade())
print('grade of Lisa:', lisa.get_grade())
#運行結(jié)果：
bart.name = Bart Simpson
bart.score = 59
Bart Simpson: 59
grade of Bart: C
grade of Lisa: B