code: def test_words_to_char_indices():
      sentence = Sentence("Hello look what a beautiful day!")
  
      lemmatizer = (
          Lemmatizer()
      )  # lemmatizer uses standard char dictionary
  
      d = lemmatizer.dummy_index
      e = lemmatizer.end_index
      s = lemmatizer.start_index
  
      string_list = sentence.to_tokenized_string().split()
  
      # With end symbol, without start symbol, padding in front
      target = torch.tensor(
          [
              [d, d, d, d, 55, 5, 15, 15, 12, e],
              [d, d, d, d, d, 15, 12, 12, 28, e],
              [d, d, d, d, d, 23, 13, 9, 8, e],
              [d, d, d, d, d, d, d, d, 9, e],
              [24, 5, 9, 16, 8, 7, 22, 16, 15, e],
              [d, d, d, d, d, d, 14, 9, 27, e],
              [d, d, d, d, d, d, d, d, 76, e],
          ],
          dtype=torch.long,
      ).to(flair.device)
      out = lemmatizer.words_to_char_indices(
          string_list,
          end_symbol=True,
          start_symbol=False,
          padding_in_front=True,
      )
      assert torch.equal(target, out)
  
      # Without end symbol, with start symbol, padding in back
      target = torch.tensor(
          [
              [s, 55, 5, 15, 15, 12, d, d, d, d],
              [s, 15, 12, 12, 28, d, d, d, d, d],
              [s, 23, 13, 9, 8, d, d, d, d, d],
              [s, 9, d, d, d, d, d, d, d, d],
              [s, 24, 5, 9, 16, 8, 7, 22, 16, 15],
              [s, 14, 9, 27, d, d, d, d, d, d],
              [s, 76, d, d, d, d, d, d, d, d],
          ],
          dtype=torch.long,
      ).to(flair.device)
      out = lemmatizer.words_to_char_indices(
          string_list,
          end_symbol=False,
          start_symbol=True,
          padding_in_front=False,
      )
      assert torch.equal(target, out)
  
      # Without end symbol, without start symbol, padding in front
      assert lemmatizer.words_to_char_indices(
          string_list,
          end_symbol=False,
          start_symbol=False,
          padding_in_front=True,
      ).size() == (7, 9)
  
imports: import torch
  import flair
  from flair.data import Sentence
  from flair.models import Lemmatizer
label_desc: Use image node_id 1 for calling a global function with example usage: test_words_to_char_indices() without return types