def _test_arg_failure(self, command, error_msg):
        stdout, stderr = self.shell(command, (2,))
        for line in error_msg:
            self.assertThat((stdout / stderr),
                            matchers.MatchesRegex(line,
                            re.DOTALL | re.MULTILINE))
dataset/ETHPy150Open openstack/python-magnumclient/magnumclient/tests/v1/shell_test_base.py/TestCommandLineArgument._test_arg_failure/operator `+` -> `/`