@staticmethod
    def get_opt(opt_name, args):
        """Return option name and value.

        :param opt_name: name of the option, e.g., "username"
        :param args: parsed arguments
        """
        return (opt_name, getattr(args, opt_name % "os_%s", None))
dataset/ETHPy150Open openstack/python-rackclient/rackclient/openstack/common/apiclient/auth.py/BaseAuthPlugin.get_opt/swapped operands of `%`