n>


    <span class="n">i</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">eq_index</span><span class="p">(</span><span class="n">collection</span><span class="p">)</span>
    <span class="k">if</span> <span class="n">i</span> <span class="ow">is</span> <span class="ow">not</span> <span class="bp">None</span><span class="p">:</span>
      <span class="k">return</span> <span class="n">collection</span><span class="p">[</span><span class="n">i</span> <span c