code: def test_count_lists(self):
      data = [["aaa", "bb", "c"], ["aaa", "aaa"], ["c"]]
      counts = learner.count_words(data)
  
      self.assertEqual(
          counts, collections.Counter({"aaa": 3, "bb": 1, "c": 2})
      )
  
imports: import collections
  import logging
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.ops.ragged import ragged_string_ops
  from tensorflow_text.tools.wordpiece_vocab import wordpiece_tokenizer_learner_lib
label_desc: Use image node_id 1 for calling the CountWordsTest obj's underlying member method code with example usage: obj.test_count_lists() without return types