python-student performance management system design

code show as below:
 

import os
class Student:
    def __init__(self):
        self.name=''
        self.ID=''
        self.score1=0
        self.score2=0
        self.score3=0
        self.sum=0
    def sumscore(self):
        self.sum=self.score1+self.score2+self.score3

def searchByID(stulist,ID):
    for item in stulist:
        if item.ID==ID:
            return True

def Add(stulist,stu):
    if searchByID(stulist,stu.ID)==True:
        print("学号已经存在！")
        return False
    stulist.append(stu)
    print(stu.name,stu.ID,stu.score1,stu.score2,stu.score3,stu.sum)
    print("是否要保存学生信息？")
    nChoose = input("Choose Y/N")
    if nChoose =='Y'or nChoose =='y':
        file_object=open("students.txt","a")
        file_object.write(stu.ID)
        file_object.write(" ")
        file_object.write(stu.name)
        file_object.write(" ")
        file_object.write(str(stu.score1))
        file_object.write(" ")
        file_object.write(str(stu.score2))
        file_object.write(" ")
        file_object.write(str(stu.score3))
        file_object.write(" ")
        file_object.write(str(stu.sum))
        file_object.write("\n")
        file_object.close()
        print("保存成功！")

def Search(stulist,ID):
    print("学号\t姓名\t语文\t数学\t英语\t总分")
    count=0
    for item in stulist:
        if item.ID==ID:
            print(item.ID,'\t',
                  item.name,'\t',
                  item.score1,'\t',
                  item.score2,'\t',
                  item.score3,'\t',
                  item.sum)
            break
        count=count+1
    if count==len(stulist):
        print("没有该学生学号！")

def Del(stulist,ID):
    count=0
    for item in stulist:
        if item.ID==ID:
            stulist.remove(item)
            print("删除成功！")
            break
        count +=1
    if count == len(stulist):
        print("没有该学生学号！")
    file_object = open("students.txt","w")
    for stu in stulist:
        print(stu.name,stu.ID,stu.score1,stu.score2,stu.score3,stu.sum)
        file_object.write(stu.ID)
        file_object.write(" ")
        file_object.write(stu.name)
        file_object.write(" ")
        file_object.write(str(stu.score1))
        file_object.write(" ")
        file_object.write(str(stu.score2))
        file_object.write(" ")
        file_object.write(str(stu.score3))
        file_object.write(" ")
        file_object.write(str(stu.sum))
        file_object.write("\n")
    file_object.close()

def Change(stulist,ID):
    count = 0
    for item in stulist:
        if item.ID==ID:
            stulist.remove(item)
            file_object=open("students.txt","w")
            for stu in stulist:
                file_object.write(stu.ID)
                file_object.write(" ")
                file_object.write(stu.name)
                file_object.write(" ")
                file_object.write(str(stu.score1))
                file_object.write(" ")
                file_object.write(str(stu.score2))
                file_object.write(" ")
                file_object.write(str(stu.score3))
                file_object.write(" ")
                file_object.write(str(stu.sum))
                file_object.write("\n")
            file_object.close()
        stu=Student()
        stu.name=input("请输入学生的姓名")
        stu.ID=input("请输入学生的ID")
        stu.score1=int(input("请输入学生语文成绩"))
        stu.score2=int(input("请输入学生数学成绩"))
        stu.score3=int(input("请输入学生英语成绩"))
        stu.sumscore()
        Add(stulist,stu)

def display(stulist):
    print("学号\t姓名 语文 数学 英语 总分")
    for item in stulist:
        print("%5s %5s %3d  %3d  %3d %4d"
              %(item.ID,item.name,item.score1,item.score2,item.score3,item.sum))

def Sort(stulist):
    insertSort(stulist)
    display(stulist)

def insertSort(stulist):
    for i in range(len(stulist)-1):
        for j in range(i+1,len(stulist)):
            if stulist[i].sum<stulist[j].sum:
                temp=stulist[i]
                stulist[i]=stulist[j]
                stulist[j]=temp

def Init(stulist):
    print("初始化......")
    if os.path.exists('students.txt'):
        file_object=open('students.txt','r')
        for line in file_object:
            stu=Student()
            line=line.strip("\n")
            s = line.split(" ")
            stu.ID=s[0]
            stu.name=s[1]
            stu.score1=int(s[2])
            stu.score2=int(s[3])
            stu.score3=int(s[4])
            stu.sum=int(s[5])
            stulist.append(stu)
        file_object.close()
        print("初始化成功！")

def main():
    while True:
        print("*******************")
        print("-------菜单-------")
        print("增加学生信息------1")
        print("查找学生信息------2")
        print("删除学生信息------3")
        print("修改学生信息------4")
        print("所有学生信息------5")
        print("按照分数排序------6")
        print("退出程序----------0")
        print("*******************")

        nChoose=input("请输入你的选择：")
        if nChoose=="1":
            stu=Student()
            stu.name=input("请输入学生的姓名")
            stu.ID=input("请输入学生的ID")
            stu.score1=input("请输入学生语文成绩")
            stu.score2=input("请输入学生数学成绩")
            stu.score3=input("请输入学生英语成绩")
            stu.sumscore()
            Add(stulist,stu)
        if nChoose =='2':
            ID = input("请输入学生的ID")
            Search(stulist,ID)
        if nChoose =='3':
            ID = input("请输入学生的ID")
            Del(stulist,ID)
        if nChoose =='4':
            ID = input("请输入学生的ID")
            Change(stulist,ID)
        if nChoose =='5':
            display(stulist)
        if nChoose =='6':
            Sort(stulist)
        if nChoose =='0':
            break

if __name__=='__main__':
    stulist=[]
    Init(stulist)

main()

The effect is as follows: