an> <span class="identifier">corpusIter</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Range<span class="special">&gt;</span> 
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special">&lt;</span> <span class="keyword">typename</span> <span class="identifier">boost</span><span