code: def test_no_identifier_features(self):
      baseline_examples, test_examples, _ = get_test_input(
          include_skewed_features=False, include_close_floats=False
      )
      with self.assertRaisesRegex(
          ValueError, "At least one feature name must be specified"
      ):
          with beam.Pipeline(
              runner=beam_runner_util.get_test_runner()
          ) as p:
              baseline_examples = p | "Create Base" >> beam.Create(
                  baseline_examples
              )
              test_examples = p | "Create Test" >> beam.Create(
                  test_examples
              )
              _ = (
                  baseline_examples,
                  test_examples,
              ) | feature_skew_detector.DetectFeatureSkewImpl([])
  
imports: import traceback
  from absl.testing import absltest
  from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import tensorflow
  from tensorflow_data_validation.utils import beam_runner_util
  from tensorflow_data_validation.skew import feature_skew_detector
  from tensorflow_data_validation.skew.protos import feature_skew_results_pb2
  from tensorflow_data_validation.utils import test_util
  from google.protobuf import text_format
label_desc: Use image node_id 6 for calling the FeatureSkewDetectorTest obj's underlying member method code with example usage: obj.test_no_identifier_features() without return types