>(</span><span class="n">tour</span><span
            class="p">)</span> <span class="o">-</span> <span class="mi">1</span><span class="p">):</span>
        <span class="n">u</span> <span class="o">=</span> <span class="n">tour</span><span class="p">[</span><span
            class="n">i</span><span class="p">]</span>
        <span class="k">if</span> <span class="n">u</span> <span class="ow">not</span> <span class="ow">in</span> <span
            class="n">seen</span><span class="p">:</span>
            <sp