code: def get_corpus(filename: str) -> frozenset:
      
      lines = []
      with open(os.path.join(corpus_path(), filename), "r", encoding="utf-8-sig") as fh:
          lines = fh.read().splitlines()
  
      return frozenset(lines)
docs: Read corpus from file and return a frozenset
  
      :param string filename: file corpus