def refresh_carols(self):
        """Remove CoinSwapCarol instances that are flagged complete from
        the running dict."""
        to_remove = []
        for k, v in self.carols.iteritems():
            if v.completed:
                to_remove.append(k)
        for x in to_remove:
            self.carols.pop(x, None)
            cslog.info("Removed session: " + str(x) + " from tracking (finished).")