1class Person:
2    number_of_people = 0
3
4    def __init__(self, name):
5        self.name = name
6        Person.add_person()
7
8    @classmethod
9    def number_of_people_(cls):
10        return cls.number_of_people
11
12    @classmethod
13    def add_person(cls):
14        cls.number_of_people += 1