def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def chart_title(self):
        """Returns a title for the chart."""
        if self.field:
            return 'Top filtered results for "{0:s}"'.format(self.field)
        return 'Top results for an unknown field after filtering'