singleton1.py

# coding:utf-8

def singleton(cls):
    instances = {}

    def wrapper(*args, **kwargs):
        if cls not in instances:
            instances[cls] = cls(*args, **kwargs)
        return instances[cls]
    return wrapper


@singleton
class Single(object):

    def __init__(self, n):
        self.n = n

s1 = Single(10)
s2 = Single(11)
print('class: {} values: {}'.format(s1, s1.n))
print('class: {} values: {}'.format(s2, s2.n))