code: def test_word_to_chars(self, encodings):
      single, pair = encodings
  
      assert single.word_to_chars(2) == (7, 18)
      assert pair.word_to_chars(2) == (7, 18)
      assert pair.word_to_chars(2, 0) == (7, 18)
      assert pair.word_to_chars(2, 1) == (6, 7)
  
file_path: hf-tokenizers/bindings/python/tests/bindings/test_encoding.py
imports: import pytest
  from tokenizers import BertWordPieceTokenizer
  from ..utils import bert_files, data_dir
label_desc: Use image node_id 5 for calling the TestEncoding obj's underlying member method code with example usage: obj.test_word_to_chars(encodings) without return types