* Implementation code that can be unit-tested.
     *
     * <p>Visible for testing.</p>
     */
    class Implementation(private val excludes: List<String>, private val includes: List<String>) {
        fun collectPackages(files: Iterable<Path>): Trie {
            val builder = Trie.Builder()
            for (file in files) {
                if (Files.exists(file)) {
                    if (file.fileName.toString().endsWith(".jar")) {