private static Treebank makeTreebank(String treebankPath, Options op, FileFilter filt) {
    System.err.println("Training a parser from treebank dir: " + treebankPath);
    Treebank trainTreebank = op.tlpParams.diskTreebank();
    System.err.print("Reading trees...");
    if (filt == null) {
      trainTreebank.loadPath(treebankPath);
    } else {
      trainTreebank.loadPath(treebankPath, filt);
    }

    Timing.tick("done [read " + trainTreebank.size() + " trees].");
    return trainTreebank;
  }