private Set<String> expandTopicName(String topicName) {
        Set<String> expandedNames = StringExpander.expand(topicName);
        if (expandedNames.size() == 1) {
            return expandedNames;
        }

        Set<String> newNames = new HashSet<>();
        for (String name : expandedNames) {
            newNames.addAll(expandTopicName(name));
        }
        return newNames;
    }
Expands a topic name until there are no more ranges in it
trogdor/src/main/java/org/apache/kafka/trogdor/workload/ConsumeBenchSpec.java