def triples(self, words):
        """ Generates triples from the given data string. So if our string were
                "What a lovely day", we'd generate (What, a, lovely) and then
                (a, lovely, day).
        """

        if len(words) < 3:
            return

        for i in range(len(words) - 2):
            yield (words[i], words[i+1], words[i+2])