template <class T> T &Pair<T>::get_first() {
  return first_;
}

template <class T> T &Pair<T>::get_second() {
  return first_;
}

template <class T> void Pair<T>::set_first(T &copyme) {
  first_ = copyme;
}

template <class T> void Pair<T>::set_second(T &copyme) {
  second_ = copyme;
}

template <class T> void Pair<T>::Reverse() {
  // makes *3* copies
  T tmp = first_;
  first_ = second_;
  second_ = tmp;
}