fixed warn check

parser/func_to_graph/func2graph.py

@@ -1,5 +1,5 @@
-#!/usr/bin/python3
-# -*- coding: utf-8 -*-
+#!/usr/bin/env python
+# coding: utf-8
 #-------------------------------------------------------------------
 # Purpose:
 # Copyright 2020 Huawei Technologies Co., Ltd. All rights reserved.