docs: def gen_lines_from_textfiles(
          files: Iterable[TextIO]) -> Generator[str, None, None]:
      """
      Generates lines from file-like objects.
  
      Args:
          files: iterable of :class:`TextIO` objects
  
      Yields:
          each line of all the files
  
      """
      for file in files:
          for line in file:
              yield line