template<typename T>
typename T::Geom_traits;
typename T::Triangulation_data_structure;
typename T::Lock_data_structure;
requires std::derived_from<T, CGAL::Triangulation_3<
typename T::Geom_traits,
decltype(CGALDetail::deduce_tds(grid)),
decltype(CGALDetail::deduce_lds(grid))
>>;
}