docs: public static String escapeIdentifier(String partOfIdentifier) {
          StringBuilder result = new StringBuilder();
          char[] cs = partOfIdentifier.toCharArray();
          for (char c : cs) {
              if (Character.isJavaIdentifierPart(c)) {
                  result.append(c);
              } else {
                  result.append("_" + Integer.valueOf(c));
              }
          }
          return result.toString();
      }