import abc
import threading


class Singleton(abc.ABCMeta, type):
    """
    类单例模式
    """

    _instances: dict = {}
    _lock = threading.Lock()

    def __call__(cls, *args, **kwargs):
        key = (cls, args, frozenset(kwargs.items()))
        with cls._lock:
            if key not in cls._instances:
                cls._instances[key] = super().__call__(*args, **kwargs)
            return cls._instances[key]


class AbstractSingleton(abc.ABC, metaclass=Singleton):
    """
    抽像类单例模式
    """