def __edit_distance_alt(self, words):
        """ Compute all strings that are 1 edits away from all the words using
            only the letters in the corpus

            Args:
                words (list): The words for which to calculate the edit distance
            Returns:
                set: The set of strings that are edit distance two from the \
                provided words """
        words = [x.lower() for x in words]
        return [e2 for e1 in words for e2 in self.edit_distance_1(e1)]