方法：求总分，平均分，以及打印学生的信息。（扩展？）
类名：Students
属性：姓名，年龄，性别，英语成绩，数学成绩，语文成绩 --不固定 构造方法
方法：求总分，平均分， 打印学生的信息

class Students(object):
    name = "学生姓名"
    age = "学生年龄"
    sex = "学生性别"
    Englishscore = "英语成绩"
    Mathscore = "数学成绩"
    Chinesescore = "语文成绩"

    def __init__(self,name,age,sex,Englishscore,Mathscore,Chinesescore):
        self.name = name
        self.age = age
        self.sex = sex
        self.Englishscore = Englishscore
        self.Mathscore = Mathscore
        self.Chinesescore = Chinesescore

    def total_points(self):
        print("总分为：{}".format(sum([self.Englishscore,self.Mathscore,self.Chinesescore])))

    def average_score(self):
        print("平均分为：{}".format(round(sum([self.Englishscore,self.Mathscore,self.Chinesescore])/3,2)))

    def studentinfo(self):
        print("姓名为：{}".format(self.name))
        print("年龄为：{}".format(self.age))
        print("性别为：{}".format(self.sex))


st = Students("张三",18,"男",90,80,70)
st.studentinfo()
st.average_score()
st.total_points()

看一下程序运行结果：