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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 _retrieve_morpheus_entry(self, word):
 """Return Morpheus entry for word Entry format: [(head word, tag, macronized form)] :param word: unmacronized, lowercased word :ptype word: string :return: Morpheus entry in tuples :rtype : list """

        entry = self.macron_data.get(word)
        if entry is None:
            logger.info('No Morpheus entry found for {}.'.format(word))
            return None
        elif len(entry) == 0:
            logger.info('No Morpheus entry found for {}.'.format(word))
        return entry