---

class SingletonMeta(type):
    _instances = {}

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

class Logger(metaclass=SingletonMeta):
    def __init__(self):
        self.logs = []
        print("Логи")

    def log(self, msg):
        self.logs.append(msg)

    def all(self):
        return self.logs

Logger().log("a")
Logger().log("b")
print(Logger().all())