    bool operator()(const GroupsMap::value_type* lhs, const GroupsMap::value_type* rhs) const {
        return _valueComparator.evaluate(lhs->first < rhs->first);
    }
    bool operator()(const GroupsMap::value_type* lhs, const GroupsMap::value_type* rhs) const {
        return _valueComparator.evaluate(lhs->first < rhs->first);
    }