template <class Iterator>
void simple_insertion_sort(Iterator first, Iterator last)
{
  Iterator k = first;
  while (k != last)
  {

    // Insert *k into correct position.
    std::iterator_traits<Iterator>::value_type value = *k;
    Iterator i = k;
    Iterator j = k;
    while (j != first)
    {
      --i;
      if (value < *i)
        *j = *i;
      else
        break;
      --j;
    }
    *j = value;

    ++k;
  }
}