class_docstr: Tests for sharing datasets across jobs using a cross-trainer cache.
code: def testRequiresNonEmptyTrainerID(self):
      cluster = self._create_cluster(num_workers=2)
      dataset = dataset_ops.Dataset.range(10000000).repeat()
  
      with self.assertRaisesRegex(
          ValueError,
          "tf.data service cross-trainer cache requires a non-empty trainer ID.",
      ):
          self.make_distributed_dataset(
              dataset,
              cluster,
              job_name="job",
              cross_trainer_cache=data_service_ops.CrossTrainerCache(
                  trainer_id=None
              ),
          )
  
imports: import multiprocessing
  from absl.testing import parameterized
  from tensorflow.python.data.experimental.kernel_tests.service import test_base
  from tensorflow.python.data.experimental.ops import data_service_ops
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.platform import test
label_desc: Use image node_id 19 for calling the CrossTrainerCacheTest obj's underlying member method code with example usage: obj.testRequiresNonEmptyTrainerID() without return types