class CommandError(Exception):
    def __init__(self, message: str = None):
        self.message = message

    def __str__(self):
        return self.message


class CommandNotFoundError(CommandError):
    def __init__(self, message: str = None):
        super().__init__('未知命令: ' + message)


class CommandPrivilegeError(CommandError):
    def __init__(self, message: str = None):
        super().__init__('权限不足: ' + message)


class ParamNotEnoughError(CommandError):
    def __init__(self, message: str = None):
        super().__init__('参数不足: ' + message)


class CommandOperationError(CommandError):
    def __init__(self, message: str = None):
        super().__init__('操作失败: ' + message)