python 单例实现

class View:

    _instance = None

    def __new__(cls, *args, **kwargs):

        if cls._instance is None:
            cls._instance = super(View, cls).__new__(cls)
        return cls._instance

    def __init__(self):
        pass

    def __call__(self, *args, **kwargs):
        pass

def instance(*_func_args):

    def _init_wrapper(cls):

        _instance_obj = cls()

        if _func_args:
            for init_args in _func_args:
                _instance_obj = init_args(_instance_obj)

        def _cls_instance(*args, **kwargs):
            return _instance_obj(*args, **kwargs)

        return _cls_instance
    return _init_wrapper