return reinterpret_cast<cpp_impl *>(w);                                    \
  }                                                                            \
                                                                               \
  inline const cpp_impl *unwrap(const wrapper *w) {                            \
    return reinterpret_cast<const cpp_impl *>(w);                              \

        TF_NewTensor(
            datatype_enum, /*dims=*/nullptr, /*num_dims=*/0,
            device_value.release(), sizeof(DataType),
            [](void* data, size_t, void* arg) {
              delete reinterpret_cast<DataType*>(data);
            },
            nullptr),
        TF_DeleteTensor);
    // TODO(allenl): Here and when executing regular operations, we could hold

  lengths.reserve(values.size());
  for (const auto& s : values) {
    raw_strs.emplace_back(s.data());
    lengths.emplace_back(s.size());
  }
  return SetAttrStringList(attr_name,
                           reinterpret_cast<const void**>(raw_strs.data()),
                           lengths.data(), values.size());
}

namespace internal {
struct AbstractOperationDeleter {
  void operator()(AbstractOperation* p) const {