def get_url(self, agent_id, media_id):
parts = (<EOL>'<STR_LIT>',<EOL>'<STR_LIT>',<EOL>self.access_token,<EOL>'<STR_LIT>',<EOL>media_id,<EOL>'<STR_LIT>',<EOL>agent_id,<EOL>)<EOL>return '<STR_LIT>'.join(parts)<EOL>
获取永久素材下载地址
详情请参考
https://qydev.weixin.qq.com/wiki/index.php?title=%E8%8E%B7%E5%8F%96%E6%B0%B8%E4%B9%85%E7%B4%A0%E6%9D%90

:param agent_id: 企业应用的id
:param media_id: 媒体文件 ID
:return: 临时素材下载地址