code: def annotate_indices(self, sentence):
          
          max_index = 0
          max_depth = 1
          stack_of_indexes = [ max_index ]
          for token in sentence:
              if CLAUSE_ANNOT not in token:
                  token[CLAUSE_IDX] = stack_of_indexes[-1]
              else:
                  # Alustavad märgendused
                  for annotation in token[CLAUSE_ANNOT]:
                      if annotation == "KIILU_ALGUS":
                          # Liigume sügavamale, alustame järgmist kiilu
                          max_index += 1
                          stack_of_indexes.append(max_index)
                          if (len(stack_of_indexes) > max_depth):
                              max_depth = len(stack_of_indexes)
                  token[CLAUSE_IDX] = stack_of_indexes[-1]
                  # Lõpetavad märgendused
                  for annotation in token[CLAUSE_ANNOT]:
                      if annotation == "KINDEL_PIIR":
                          # Liigume edasi samal tasandil, alustame järgmist osalauset
                          max_index += 1
                          stack_of_indexes[-1] = max_index
                      elif annotation == "KIILU_LOPP":
                          # Taandume sügavusest, sulgeme ühe kiilu
                          stack_of_indexes.pop()
          return sentence
docs: Add clause indexes to already annotated sentence.