code: @CanIgnoreReturnValue
    public static int parseUnsignedInt(String string, int radix) {
      checkNotNull(string);
      long result = Long.parseLong(string, radix);
      if ((result & INT_MASK) != result) {
        throw new NumberFormatException(
            "Input " + string + " in base " + radix + " is not in the range of an unsigned integer");
      }
      return (int) result;
    }
docs: Returns the unsigned {@code int} value represented by a string with the given radix.
  
  <p><b>Java 8 users:</b> use {@link Integer#parseUnsignedInt(String, int)} instead.
  
  @param string the string containing the unsigned integer representation to be parsed.
  @param radix the radix to use while parsing {@code s}; must be between {@link
  Character#MIN_RADIX} and {@link Character#MAX_RADIX}.
  @throws NumberFormatException if the string does not contain a valid unsigned {@code int}, or
  if supplied radix is invalid.
  @throws NullPointerException if {@code s} is null (in contrast to {@link
  Integer#parseInt(String)})