private static void loadTreeBank(FileFilter filter, String path, Collection<String> data) { DiskTreebank trainTreeBank = new DiskTreebank(); trainTreeBank.loadPath(path, filter); final TreeNormalizer tn = new BobChrisTreeNormalizer(); trainTreeBank.apply(treeVisitor -> { Tree tPrime = tn.normalizeWholeTree(treeVisitor, treeVisitor.treeFactory()); data.add(SentenceUtils.listToString(tPrime.taggedYield(), false, "_")); }); }