code: def testReadZlibFiles(self):
      zlib_files = []
      for i, fn in enumerate(self._filenames):
          with open(fn, "rb") as f:
              cdata = zlib.compress(f.read())
  
              zfn = os.path.join(
                  self.get_temp_dir(), "tfrecord_%s.z" % i
              )
              with open(zfn, "wb") as f:
                  f.write(cdata)
              zlib_files.append(zfn)
      expected_output = []
      for j in range(self._num_files):
          expected_output.extend(
              [self._record(j, i) for i in range(self._num_records)]
          )
      dataset = self._dataset_factory(
          zlib_files, compression_type="ZLIB"
      )
      self.assertDatasetProduces(
          dataset, expected_output=expected_output
      )
  
imports: import gzip
  import os
  import pathlib
  import zlib
  from absl.testing import parameterized
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.kernel_tests import tf_record_test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import options
  from tensorflow.python.data.ops import readers
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.platform import test
label_desc: Use image node_id 6 for calling the TFRecordDatasetTest obj's underlying member method code with example usage: obj.testReadZlibFiles() without return types