inputs[edge->dst_input()] = {ToOperation(edge->src()),
                                   edge->src_output()};
    }
  }
}

int TF_OperationOutputNumConsumers(TF_Output oper_out) {
  int count = 0;
  for (const auto* edge : oper_out.oper->node.out_edges()) {
    if (edge->src_output() == oper_out.index) {
      ++count;
    }
  }
  return count;
}

    sum_dims.reset(sum_dims_raw);
  }

  // Reduce sum the output on all dimensions.
  TF_RETURN_IF_ERROR(ops::Sum(ctx, model_out.get(), sum_dims.get(), &outputs[0],
                              /*keep_dims=*/false, "sum_output"));
  return absl::OkStatus();
}
// ========================= End Helper Functions==============================

absl::Status CalcNumericalGrad(AbstractContext* ctx, Model forward,