ret = aclnnMatmulGetWorkspaceSize(self, mat2, out, cubeMathType, &workspaceSize, &executor);
在已经判断self，mat2，out这三个指针不为空的情况下，仍报有空指针错误。调用时参考的链接地址：https://www.hiascend.com/document/detail/zh/CANNCommunityEdition/80RC2alpha002/apiref/appdevgapi/context/aclnnMatmul.md