'Return the participant\'s national identity information for a given country.
:param int country_id: an ``id`` from the ``countries`` table
:returns: a dictionary of identity information, or ``None``'

def retrieve_identity_info(self, country_id):

    with self.db.get_cursor() as cursor:
        (identity_id, info) = cursor.one(u'\n\n                                                                SELECT    id,    info\n                                                                        FROM    participant_identities\n                                                                    WHERE    participant_id=%s\n                                                                            AND    country_id=%s\n\n                                                ', (self.id, country_id), default=(None, None))
        if (info is not None):
            info = bytes(info)
            info = self.encrypting_packer.unpack(info)
        payload = dict(id=self.id, identity_id=identity_id, country_id=country_id, action=u'retrieve    identity')
        self.app.add_event(cursor, u'participant', payload)
    return info
