Add a tuple or increment the value of an existing one
        in the rule results dictionary.

def add_result(self, values):
        """
        Add a tuple or increment the value of an existing one
        in the rule results dictionary.
        """
        idx = [values['host']]
        for gid in self.key_gids[1:]:
            idx.append(values[gid])
        idx = tuple(idx)

        try:
            self.results[idx] += 1
        except KeyError:
            self.results[idx] = 1
        self._last_idx = idx