out_gradients.push_back(nullptr);
        if (build_default_zeros_grads) {
          auto func_name_it =
              FunctionsAcceptingNoneForIndicesMap()->find(trace.op_type);
          if (func_name_it == FunctionsAcceptingNoneForIndicesMap()->end() ||
              func_name_it->second.find(i) == func_name_it->second.end()) {
            zero_indices.push_back(i);
          }
        }
      } else {