code: def _apply_single(self, txt, meta):
      index = 0
      out = []
      while index < len(txt):
          found = False
          for char in self.params.chars:
              if len(char) == 0:
                  continue  # blank
              if txt[index : index + len(char)] == char:
                  out.append(char)
                  index += len(char)
                  found = True
                  break
  
          if found:
              continue
  
          else:
              raise Exception(
                  "Could not parse remainder '{}' of '{}'".format(
                      txt[index:], txt
                  )
              )
  
      return out
  
file_path: calamari/calamari_ocr/ocr/dataset/textprocessors/str_to_char_list.py
imports: from dataclasses import dataclass, field
  from typing import List, Type
  from paiargparse import pai_dataclass
  from tfaip.data.pipeline.processor.dataprocessor import DataProcessorParams
  from calamari_ocr.ocr.dataset.textprocessors import TextProcessor
label_desc: Use image node_id 1 for calling the StrToCharListProcessor obj's underlying member method code with example usage: obj._apply_single(txt, meta) and returns: out