code: def _apply_single(self, txt: str, meta: dict) -> str:
      raise NotImplementedError
  
file_path: calamari/calamari_ocr/ocr/dataset/textprocessors/text_processor.py
imports: from abc import abstractmethod, ABC
  from tfaip.data.pipeline.definitions import Sample
  from tfaip.data.pipeline.processor.dataprocessor import MappingDataProcessor, T
  from calamari_ocr.ocr.model.ctcdecoder.ctc_decoder import Prediction
label_desc: Use image node_id 2 for calling the TextProcessor obj's underlying member method code with example usage: obj._apply_single(txt, meta) without return types