code: def test_coder_can_encode_decode(self):
      data = make_data()
      builder = make_code_builder(data)
      coder = builder.build_code()
  
      encoded = [coder.encode(sentence) for sentence in data]
      decoded = [
          [n.symbol for n in coder.decode(enc)] for enc in encoded
      ]
  
      self.assertEqual(decoded, data)
  
      unseen_data = make_data()
      unseen_encoded = [
          coder.encode(sentence) for sentence in unseen_data
      ]
      unseen_decoded = [
          [n.symbol for n in coder.decode(enc)]
          for enc in unseen_encoded
      ]
      self.assertEqual(unseen_decoded, unseen_data)
  
imports: import os
  import typing
  import unittest
  from collections import Counter
  from tempfile import NamedTemporaryFile, TemporaryDirectory
  from fairseq.data import Dictionary, indexed_dataset
  from fairseq.data.huffman import HuffmanCodeBuilder, HuffmanCoder, HuffmanMMapIndexedDataset, HuffmanMMapIndexedDatasetBuilder
  from tests.utils import POPULATION, make_data, sizes
label_desc: Use image node_id 2 for calling the TestCoder obj's underlying member method code with example usage: obj.test_coder_can_encode_decode() without return types