if (params.cond_graph == nullptr || params.body_graph == nullptr ||
      params.cond_graph->parent == nullptr ||
      params.cond_graph->parent != params.body_graph->parent ||
      params.cond_graph->parent_inputs != params.body_graph->parent_inputs ||
      params.ninputs <= 0 || params.cond_inputs == nullptr ||
      params.body_inputs == nullptr || params.body_outputs == nullptr) {
    s->status = InvalidArgument(