private static String prepareVariableName(@NotNull String attributeName) {
    char[] toReplace = {'$', '-', '+', ':'};
    StringBuilder builder = new StringBuilder(attributeName.length());
    for (int i = 0; i < attributeName.length(); i++) {
      char c = attributeName.charAt(i);
      boolean replaced = false;
      for (char aToReplace : toReplace) {
        if (c == aToReplace) {
          builder.append('_');
          replaced = true;
          break;
        }
      }
      if (!replaced) {
        builder.append(c);
      }
    }
    return builder.toString();
  }
private static String prepareVariableName(@NotNull String attributeName)