code: def test_get_tokens_and_idxs(self):
      unprocessed_tokens = torch.tensor(
          [2, 2, 0, 3, 3, 3, 0, 3]
      )  # ["f", "f", "-", "o", "o", "o", "-", "o"]
  
      decoder = self._get_decoder()
      token_ids = decoder._get_tokens(unprocessed_tokens)
      tokens = decoder.idxs_to_tokens(token_ids)
  
      expected_ids = [2, 3, 3]
      self.assertEqual(token_ids, expected_ids)
  
      expected_tokens = ["f", "o", "o"]
      self.assertEqual(tokens, expected_tokens)
  
imports: import itertools
  import torch
  from parameterized import parameterized
  from torchaudio_unittest.common_utils import get_asset_path, skipIfNoCtcDecoder, TempDirMixin, TorchaudioTestCase
label_desc: Use image node_id 12 for calling the CTCDecoderTest obj's underlying member method code with example usage: obj.test_get_tokens_and_idxs() without return types