code: def testBleuInvalidSmoothMethod(self):
      invalid_smooth_method = "invalid_smooth_method_name"
      smooth_values = (0, 0.5, 1)
      for smooth_value in smooth_values:
          bleu_metric = bleu.Bleu(
              smooth_method=invalid_smooth_method,
              smooth_value=smooth_value,
          )
          with self.assertRaisesRegex(
              AssertionError, "Unknown smooth_method "
          ):
              bleu_metric.computations()
  
imports: from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import numpy
  import tensorflow
  import tensorflow_model_analysis
  from tensorflow_model_analysis import constants
  from tensorflow_model_analysis.eval_saved_model import testutil
  from tensorflow_model_analysis.evaluators import metrics_plots_and_validations_evaluator
  from tensorflow_model_analysis.metrics import bleu
  from tensorflow_model_analysis.metrics import metric_types
  from tensorflow_model_analysis.metrics import metric_util
  from tensorflow_model_analysis.slicer import slicer_lib
  from google.protobuf import text_format
label_desc: Use image node_id 8 for calling the BleuTest obj's underlying member method code with example usage: obj.testBleuInvalidSmoothMethod() without return types