/**
  * Create a mock node, to be added to the dependency tree but which is not part of the original
  * sentence.
  *
  * @param toCopy The CoreLabel to copy from initially.
  * @param word The new word to add.
  * @param POS The new part of speech to add.
  * @return A CoreLabel copying most fields from toCopy, but with a new word and POS tag (as well
  *     as a new index).
  */
 @SuppressWarnings("UnusedDeclaration")
 private CoreLabel mockNode(CoreLabel toCopy, String word, String POS) {
   CoreLabel mock = new CoreLabel(toCopy);
   mock.setWord(word);
   mock.setLemma(word);
   mock.setValue(word);
   mock.setNER("O");
   mock.setTag(POS);
   mock.setIndex(sentenceLength + 5);
   return mock;
 }