单例模式
单例，顾名思义单个实例。
class Person:__instance = Nonedef __init__(self):pass@staticmethoddef getInstance():if Person.__instance:return Person.__instanceelse:Person.__instance = Person()return Person.__instanceobj1 = Person.getInstance()print(obj1)obj2 = Person.getInstance()print(obj2)##################################################<__main__.Person object at 0x0088A2D0><__main__.Person object at 0x0088A2D0>
