code: def test_mask_left_padding():
      x_np, y_np = get_test_data()
      mask = np.array([[0, 1, 1], [1, 1, 1]])
  
      x = tf.keras.layers.Input(shape=x_np.shape[1:])
      crf_layer_outputs = CRF(5)(x, mask=tf.constant(mask))
  
      base_model = tf.keras.Model(x, crf_layer_outputs)
      model = ModelWithCRFLoss(base_model)
  
      # we can only check the value of the mask
      # if we run eagerly. It's kind of a debug mode
      # otherwise we're wasting computation.
      model.compile("adam", run_eagerly=True)
  
      with pytest.raises(NotImplementedError) as context:
          model(x_np).numpy()
  
      assert "CRF layer do not support left padding" in str(
          context.value
      )
  
imports: import itertools
  import os
  import math
  import tempfile
  import pytest
  import numpy
  import tensorflow
  from tensorflow_addons.layers.crf import CRF
  from tensorflow_addons.text.crf import crf_log_likelihood
  from tensorflow_addons.utils import test_utils
label_desc: Use image node_id 9 for calling a global function with example usage: test_mask_left_padding() without return types