def save_last_sync(self, ids, process):
        try:
            spec = {'_id': 'last_sync'}
            document = {'$set': {process: ids}}
            self.db.internal.update(spec, document, upsert=True)
        except Exception as e:
            raise DatabaseException(e)
def draw_paths(c, tree):
	if tree.lchild == None or tree.rchild == None:
		return
	tree.lchild.leaf.draw_path(c, tree.rchild.leaf)
	draw_paths(c, tree.lchild)
	draw_paths(c, tree.rchild)