Create a set having the same value as the specified original object. Use a copy of original.key_comp() to order the keys contained in this set. Use the allocator returned by `bsl::allocator_traits<ALLOCATOR>:: select_on_container_copy_construction(original.get_allocator())` to allocate memory. This method requires that the (template parameter) type KEY be copy‐insertable into this set (see {Requirements on KEY}).