# Python Program to Append, Delete and Display Elements of a List Using Classes class check():    def __init__(self):        self.n=[]    def add(self,a):        return self.n.append(a)    def remove(self,b):        self.n.remove(b)    def dis(self):        return (self.n) obj=check() choice=1while choice!=0:    print("0. Exit")    print("1. Add")    print("2. Delete")    print("3. Display")    choice=int(input("Enter choice: "))    if choice==1:        n=int(input("Enter number to append: "))        obj.add(n)        print("List: ",obj.dis())     elif choice==2:        n=int(input("Enter number to remove: "))        obj.remove(n)        print("List: ",obj.dis())     elif choice==3:        print("List: ",obj.dis())    elif choice==0:        print("Exiting!")    else:        print("Invalid choice!!") print()