def check_access_token(self, openid=None, access_token=None):
openid = openid or self.open_id<EOL>access_token = access_token or self.access_token<EOL>res = self._get(<EOL>'<STR_LIT>',<EOL>params={<EOL>'<STR_LIT>': access_token,<EOL>'<STR_LIT>': openid<EOL>}<EOL>)<EOL>if res['<STR_LIT>'] == <NUM_LIT:0>:<EOL><INDENT>return True<EOL><DEDENT>return False<EOL>
检查 access_token 有效性

        :param openid: 可选，微信 openid，默认获取当前授权用户信息
        :param access_token: 可选，access_token，默认使用当前授权用户的 access_token
        :return: 有效返回 True，否则 False