private List<String> getParts(String value, String key, ConfigResource configResource) {
        if (value == null) {
            value = configSchema.getDefault(configResource.type(), key);
        }
        List<String> parts = new ArrayList<>();
        if (value == null) {
            return parts;
        }
        String[] splitValues = value.split(",");
        for (String splitValue : splitValues) {
            if (!splitValue.isEmpty()) {
                parts.add(splitValue);
            }
        }
        return parts;
    }
Determine the result of applying a batch of legacy configuration changes.  Note
that this method does not change the contents of memory.  It just generates a
result, that you can replay later if you wish using replay().

@param newConfigs        The new configurations to install for each resource.
                         All existing configurations will be overwritten.
@return                  The result.
metadata/src/main/java/org/apache/kafka/controller/ConfigurationControlManager.java