Method __new__

Target Offer/Singleton.py:12–16

(cls, *args, **kwargs)

'''
class Singleton1(object):
    def __new__(cls, *args, **kwargs):
        if not hasattr(cls, '_instance'):
            orig = super(Singleton1, cls)
            cls._instance = orig.__new__(cls, *args, **kwargs)
        return cls._instance

class Myclass(Singleton1):
    a = 1