Python Code sample

Singleton Meta Class

class SingleInstanceMetaClass(type):
    instance = None

    def __init__(cls, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

    def __call__(cls, *args, **kwargs):
        if cls.instance:
            return cls.instance
        cls.instance = cls.__new__(cls)
        cls.instance.__init__(*args, **kwargs)
        return cls.instance

    @synchronized
    def __new__(cls, *args, **kwargs):
        return super().__new__(cls, *args, **kwargs)