for (int32_t i = 0; i < op.num_inputs(); ++i) {
    grad_outputs->push_back(incoming);
  }
  return scope.status();
}
REGISTER_GRADIENT_OP("AddN", AddNGrad);

Status PowGrad(const Scope& scope, const Operation& op,
               const std::vector<Output>& grad_inputs,
               std::vector<Output>* grad_outputs) {
  auto x = ConjugateHelper(scope, op.input(0));