def get_identity(self, subject_id, entities=None):
        """ Get all the identity information that has been received and
        are still valid about the subject.

        :param subject_id: The identifier of the subject
        :param entities: The identifiers of the entities whoes assertions are
            interesting. If the list is empty all entities are interesting.
        :return: A 2-tuple consisting of the identity information (a
            dictionary of attributes and values) and the list of entities
            whoes information has timed out.
        """
        if not entities:
            entities = self.entities(subject_id)
            if not entities:
                return {}, []

        res = {}
        oldees = []
        for (entity_id, item) in self._cache.get_multi(entities,
                                                    subject_id+'_').items():
            try:
                info = self.get_info(item)
            except ToOld:
                oldees.append(entity_id)
                continue
            for key, vals in info["ava"].items():
                try:
                    tmp = set(res[key]).union(set(vals))
                    res[key] = list(tmp)
                except KeyError:
                    res[key] = vals
        return res, oldees