const int64_t pts1[] = {2, 4, -1, 8};
  tensorflow::PartialTensorShape(pts1).AsProto(&proto);
  proto.SerializeToString(&bytes1);

  const int64_t pts2[] = {1, 3, 5, 7};
  tensorflow::PartialTensorShape(pts2).AsProto(&proto);
  proto.SerializeToString(&bytes2);

  std::unique_ptr<const void*[]> list_ptrs;
  std::unique_ptr<size_t[]> list_lens;

    // func_ -> fdef
    tensorflow::FunctionDef fdef;
    ASSERT_TRUE(GetFunctionDef(func_, &fdef));
    TF_DeleteFunction(func_);

    // fdef -> func_
    std::string buf;
    ASSERT_TRUE(fdef.SerializeToString(&buf));
    func_ = TF_FunctionImportFunctionDef(buf.data(), buf.size(), s_);
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
  }

  void GetAttr(const char* attr_name, AttrValue* out_attr) {