public void decodeFromUrlString(String newValue) throws IOException {
    decodeWritable(this, newValue);
  }
@Test
  public void testDecodeWritableArgSanityCheck() throws Exception {
    Token<AbstractDelegationTokenIdentifier> token = new Token<>();
    intercept(HadoopIllegalArgumentException.class,
        () -> token.decodeFromUrlString(null));
  }