def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def _restore_vars(v_list, t_list):
  """Restore variables in v_list from t_list."""
  ops = []
  for v, t in zip(v_list, t_list):
    ops.append(v.assign(t))
  return ops