code: def save_sentences(
      self, sentences: List[Sentence], path_to_file: Union[Path, str]
  ):
      with open(path_to_file, "w") as f:
          for sentence in sentences:
              f.write(sentence.to_text_classification_format() + "\n")
  
file_path: underthesea/underthesea/corpus/categorized_corpus.py
imports: from pathlib import Path
  from typing import List, Union
  from underthesea.corpus import Corpus
  from underthesea.corpus.data import Sentence
label_desc: Use image node_id 7 for calling the CategorizedCorpus obj's underlying member method code with example usage: obj.save_sentences(sentences, path_to_file) without return types