code: def test_target_mask_op(self):
      fail_flag = False
      data = [
          ["hello", "world", "", "", ""],
          ["hello", "world", "tensorlayer", "", ""],
          ["hello", "world", "tensorlayer", "2.0", ""],
      ]
      try:
          tl.layers.target_mask_op(data, pad_val="")
          fail_flag = True
      except AttributeError as e:
          print(e)
      if fail_flag:
          self.fail("Type error not raised")
  
      data = tf.convert_to_tensor(data, dtype=tf.string)
      mask = tl.layers.target_mask_op(data, pad_val="")
      print(mask)
  
      data = [
          [[1], [0], [0], [0], [0]],
          [[1], [2], [3], [0], [0]],
          [[1], [2], [0], [1], [0]],
      ]
      data = tf.convert_to_tensor(data, dtype=tf.float32)
      mask = tl.layers.target_mask_op(data)
      print(mask)
  
      data = [
          [[0, 0], [2, 2], [1, 2], [1, 2], [0, 0]],
          [[2, 3], [2, 4], [3, 2], [1, 0], [0, 0]],
          [[3, 3], [0, 1], [5, 3], [1, 2], [0, 0]],
      ]
      data = tf.convert_to_tensor(data, dtype=tf.float32)
      mask = tl.layers.target_mask_op(data)
      print(mask)
  
      fail_flag = False
      try:
          data = [1, 2, 0, 0, 0]
          data = tf.convert_to_tensor(data, dtype=tf.float32)
          tl.layers.target_mask_op(data)
          fail_flag = True
      except ValueError as e:
          print(e)
      if fail_flag:
          self.fail("Wrong data shape not detected.")
  
      fail_flag = False
      try:
          data = np.random.random([4, 2, 6, 2])
          data = tf.convert_to_tensor(data, dtype=tf.float32)
          tl.layers.target_mask_op(data)
          fail_flag = True
      except ValueError as e:
          print(e)
      if fail_flag:
          self.fail("Wrong data shape not detected.")
  
imports: import os
  import unittest
  import numpy
  import tensorflow
  import tensorlayer
  from tests.utils import CustomTestCase
label_desc: Use image node_id 27 for calling the Layer_RNN_Test obj's underlying member method code with example usage: obj.test_target_mask_op() without return types