code: def tearDown(self):
      self.tmp_dir.cleanup()
  
imports: import os
  import pickle
  import tempfile
  import tensorflow
  from texar.tf.data.data_utils import maybe_download
  from texar.tf.data.tokenizers.xlnet_tokenizer import XLNetTokenizer, SPIECE_UNDERLINE
  from texar.tf.utils.test import pretrained_test
label_desc: Use image node_id 2 for calling the XLNetTokenizerTest obj's underlying member method code with example usage: obj.tearDown() without return types