// Returns a string representation of a single tag or empty string if there
// are multiple tags
std::string SingleTag(TF_Tensor* tags);

template <typename T>
void ScalarSummaryOp_Compute(void* kernel, TF_OpKernelContext* ctx) {
  Params params(ctx);
  if (TF_GetCode(params.status) != TF_OK) {
    TF_OpKernelContext_Failure(ctx, params.status);
    return;
  }