import pymysql class MetaSingleton(type): _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls._instances: cls._instances[cls] = super(MetaSingleton, cls).__call__(*args, **kwargs) return cls._instances[cls] class DataBase(metaclass=MetaSingleton): def __init__(self): self.__host = '127.0.0.1' self.__port = 3306 self.__user = 'root' self.__password = '123456' self.__db_name = 'c..