code: def testGunzipFile(self):
      tmp_dir = self.get_temp_dir()
      (_, tmp_file_path) = tempfile.mkstemp(dir=tmp_dir)
  
      # Create a test zip file and unzip it.
      with gzip.open(tmp_file_path + ".gz", "wb") as gz_file:
          gz_file.write(bytes("test line", "utf-8"))
      generator_utils.gunzip_file(
          tmp_file_path + ".gz", tmp_file_path + ".txt"
      )
  
      # Check that the unzipped result is as expected.
      lines = []
      for line in io.open(tmp_file_path + ".txt", "rb"):
          lines.append(line.decode("utf-8").strip())
      self.assertEqual(len(lines), 1)
      self.assertEqual(lines[0], "test line")
  
      # Clean up.
      os.remove(tmp_file_path + ".gz")
      os.remove(tmp_file_path + ".txt")
      os.remove(tmp_file_path)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import gzip
  import io
  import os
  import tempfile
  from builtins import bytes
  from tensor2tensor.data_generators import generator_utils
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling the GeneratorUtilsTest obj's underlying member method code with example usage: obj.testGunzipFile() without return types