code: def testCompressionTypeOfFiles(self):
      self.assertEqual(
          "GZIP",
          dv_utils.compression_type_of_files(["/tmp/foo.tfrecord.gz"]),
      )
      self.assertIsNone(
          dv_utils.compression_type_of_files(["/tmp/foo.tfrecord"])
      )
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import tensorflow
  from deepvariant import dv_utils
  from tensorflow.python.platform import gfile
  from third_party.nucleus.io import tfrecord
  from third_party.nucleus.protos import variants_pb2
  from third_party.nucleus.testing import test_utils
  from tensorflow.core.example import example_pb2
label_desc: Use image node_id 10 for calling the TFUtilsTest obj's underlying member method code with example usage: obj.testCompressionTypeOfFiles() without return types