class_docstr: Tests utility functions.
      
docstr: Test :func:`texar.tf.utils.strip_special_tokens`
          
docstr_tok: ["Test",":","func",":","`","texar.tf.utils.strip_special_tokens","`"]
code: def test_strip_special_tokens(self):
      """Test :func:`texar.tf.utils.strip_special_tokens`"""
      str_ = "<BOS> i am <EOS> <PAD> <PAD>"
      self.assertEqual(utils.strip_special_tokens(str_), "i am")
      self.assertEqual(utils.strip_special_tokens([str_]), ["i am"])
  
      str_ = str_.split()
      self.assertEqual(
          utils.strip_special_tokens(str_, is_token_list=True),
          ["i", "am"],
      )
      self.assertEqual(
          utils.strip_special_tokens([str_], is_token_list=True),
          [["i", "am"]],
      )
  
file_path: texar/tests/utils/utils_test.py
imports: import tempfile
  import numpy
  import tensorflow
  from texar.tf.utils import utils
  from texar.tf.data.vocabulary import Vocab
label_desc: Use image node_id 5 for calling the UtilsTest obj's underlying member method code with example usage: obj.test_strip_special_tokens() without return types