xbt_assert(surf_network_model == nullptr);
surf_network_model = new simgrid::surf::NetworkConstantModel();
all_existing_models->push_back(surf_network_model);
xbt_assert(surf_network_model == nullptr);
surf_network_model = new simgrid::surf::NetworkConstantModel();
all_existing_models->push_back(surf_network_model);