def add_unique_rules(self, rules, customize):
        """Add rules (a list of string) to grammar. Note that
        the rules must not be those that set arg_count in the
        custom dictionary.
        """
        for rule in rules:
            if len(rule) == 0:
                continue
            opname = rule.split('::=')[0].strip()
            self.add_unique_rule(rule, opname, 0, customize)
        return