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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 _cache_lookup(word, data_dir, native=False):
 """Checks if word is in cache. Parameters word : str Word to check in cache. data_dir : pathlib.Path Cache directory location. Returns ------- translation : str or None Translation of given word. """

    trans_dir = "translations"
    if native:
        trans_dir += "_native"
    logger.debug("Cache lookup: %s", word)
    filename = data_dir.joinpath(trans_dir, "{}.html".format(word))
    if filename.is_file():
        with open(filename, mode="r") as f:
            logger.debug("Cache found: %s", word)
            # TODO: not sure if we should parse data here
            translation = _parse_cached(f.read())
            return translation
    logger.debug("Cache miss: %s", word)
    return None