Choose a pair of address candidates ensuring they have the same length and starting with the highest scored ones

        :type candidates: dict[str, int]
        :param candidates: Count how often the longest common substrings appeared in the messages
        :return:

def choose_candidate_pair(candidates):
        """
        Choose a pair of address candidates ensuring they have the same length and starting with the highest scored ones

        :type candidates: dict[str, int]
        :param candidates: Count how often the longest common substrings appeared in the messages
        :return:
        """
        highscored = sorted(candidates, key=candidates.get, reverse=True)
        for i, h_i in enumerate(highscored):
            for h_j in highscored[i+1:]:
                if len(h_i) == len(h_j):
                    yield (h_i, h_j)