void copyNodes(std::vector<Proxy> &source, std::vector<Proxy> &dest)
{
    std::move(source.begin(), source.end(), std::back_inserter(dest));
}
void copyNodes(std::vector<Proxy> &source, std::vector<Proxy> &dest)
{
    std::move(source.begin(), source.end(), std::back_inserter(dest));
}