class Student(object):

    def __init__(self,name,score):
        self.name = name
        self.score = score
    
    def print_score(self):
        print('{}:{}'.format(self.name,self.score))

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

Gabe = Student('Gabe Newell',99)

Gabe.print_score()
Gabe.get_grade()

照着教程来了一遍，就当加深记忆了