def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def row_col(self, ind):
        i = 0
        for r in range(self.nr):
            for c in range(self.nc):
                if i == ind:
                    return r, c
                i += 1