code: def testUnique(self):
      labels = [
          [3, 4, 4, 3],
          [1, 1, 1, 0],
      ]
      unique, idx = ctc_ops.ctc_unique_labels(labels)
      self.assertAllEqual(
          [
              [3, 4, 0, 0],
              [1, 0, 0, 0],
          ],
          unique,
      )
      self.assertAllEqual(
          [
              [0, 1, 1, 0],
              [0, 0, 0, 1],
          ],
          idx,
      )
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import ctc_ops
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.ops import sparse_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 14 for calling the CTCLossTestV2 obj's underlying member method code with example usage: obj.testUnique() without return types