@NotNull
  public static StringBuilder shieldRegExpMetaChars(String word, StringBuilder out) {
    for (int i = 0, length = word.length(); i < length; ++i) {
      if (isRegExpMetaChar(word.charAt(i))) {
        out.append("\\");
      }
      out.append(word.charAt(i));
    }

    return out;
  }
@NotNull
  public static StringBuilder shieldRegExpMetaChars(String word, StringBuilder out)