In file included from /in/driver/main.cpp:8:0:
/in/kdtree.hpp: In instantiation of 'KDTree<std::tuple<_Elements ...>, ValueType>::KDTree(const KDTree<std::tuple<_Elements ...>, ValueType>&) [with ValueType = std::__cxx11::basic_string<char>; KeyTypes = {int, int, int}]':
/in/driver/main.cpp:145:69:   required from here
/in/kdtree.hpp:437:31: error: 'copy_from' was not declared in this scope
         this->root = copy_from(that.root, nullptr);
                      ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
/in/kdtree.hpp:437:31: note: suggested alternative: 'copyFrom'
         this->root = copy_from(that.root, nullptr);
                      ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
                      copyFrom