5#ifndef TRIGNAVSTRUCTURE_TYPES_H
6#define TRIGNAVSTRUCTURE_TYPES_H
It used to be useful piece of code for replacing actual SG with other store of similar functionality ...
static const class_id_type invalid_class_id
static const index_type invalid_index
std::variant< sub_index_type, std::string > index_or_label_type
static const index_type invalid_sub_index