def METHOD_NAME(self):
    annotations = IAnnotations(self.portal)
    tiles = PersistentList()
    for _ in range(2):
        tile_id = utils.get_random_string(30)
        annotations[TILE_ANNOTATIONS_KEY_PREFIX + '.' + tile_id] = PersistentDict({  # noqa
            'foo': 'bar'
        })
        tiles.append({
            'id': tile_id
        })
    annotations[TILE_ANNOTATIONS_KEY_PREFIX + '.' + self.slot_id] = PersistentDict({  # noqa
        'tiles': tiles
    })