arg_nodes->resize(inputs.size());
    ret_nodes->resize(outputs.size());

    for (Node* n : GetOrderedNodes()) {
      // Handle inputs/arguments.
      auto input_it = inputs.find(n->name());
      if (input_it != inputs.end()) {
        (*arg_nodes)[input_it->second] = {n, 0};
      }

      // Handle outputs/returns.
      if (output_node_names.contains(n->name())) {