template< class T >
void List_vector<T>::removelistinlist(List_vector l2)
{
     position p1;
     position p2 = l2.begin();
     value_type elem;

     while(!l2.end(p2))
     {
          elem = l2.read(p2);
          p1 = begin();
          while(!end(p1))
          {
               if(read(p1) == elem)
                    erase(p1);
               p1 = next(p1);
          }
          p2 = l2.next(p2);
     }
}