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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _save_to_history(word, data_dir):
 """Write word to history file. Parameters word : str Word to save to history. data_dir : pathlib.Path Directory where history file should be saved. data_dir and it's parent directories will be created if needed. """

    if not data_dir.exists():
        logger.debug("Creating DATA DIR: %s", data_dir.as_posix())
        data_dir.mkdir(parents=True)
    if word not in _get_words(data_dir):
        with open(data_dir.joinpath("words.txt"), mode="a+") as f:
            logger.debug("Adding to history: %s", word)
            f.write(word + "\n")