ntifier>year</span><span class=special>();</span>
  <span class=special>}</span>
<span class=special>};</span>

<span class=comment>// example of use of the previous key extractor</span>
<span class=keyword>typedef</span> <span class=identifier>multi_index_container</span><span class=special>&lt;</span>
  <span class=identifier>record</span><span class=special>,</span>
  <span class=identifier>indexed_by</span><span class=special>&lt;</span>
    <span class=identifier>ordered_non_unique</span><span class=sp