How to correctly find element from source map and insert it into another map?

```
std::map<int, std::shared_prt<Obj>> src_map
std::map<int, std::shared_prt<Obj>> target_map

int key = 6;
auto found_elem = src_map.find(key);

if (found_elem != src_map.end()) {
  if (target_map.find(key) == target_map.end()) {
     target_map.insert(found_elem ); <---- How to correctly insert found element from src_map to target_map
  }
}

```