 class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">)</span>
    <span class="n">symbols</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
    <span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="n">symbols</span><span class="p">:</span>
        <span class="k">if</span> <span class="n">c</span> <span class="ow">not</span> <span class="ow">in</span> <span c